BMW 850I vs BMW M4

What's the difference?

Does the world really need a car as outrageously loud, over-the-top, exclusive and stupidly fast as BMW’s new 8 Series? Obviously not, but BMW clearly felt that its range, and its customers, could do with something like this. On paper, and even from the kerb, it seems a strange beast - luxurious and yet lightning quick - but from the driver’s seat it just instantly makes sense. And makes you smile. Scarily, there’s an even faster 8 Series Competition version to come…

We cannot think of a faster or more invigorating four-seater luxury convertible for the money than the new M4 Competition.

Finally, after years of devastatingly fast droptops with remote steering and an unforgiving ride, the G83 generation discovers refinement and sophistication to go with its supersonic speed.

There’s terrific talent on tap here that no rival can even come close to right now. BMW is on a roll and this is the first M4 convertible that can sit proudly alongside the best of its classic M3 ancestors.

In terms of improving on the car it’s replacing, the new 8 Series pretty much smacks it out of the park. Time has not been kind to vehicles fitted with pop-up headlights and the previous 8 Series, which roamed the planet in limited numbers from 1989 to 1999, with now-unimaginable V12 engines, seems a strange-looking beast, with its tiny little kidney grille almost hiding beneath a BMW badge.

The new M850i is a simply stunning looking beast, particularly in Coupe form (the Convertible is not ugly, but it just doesn’t look as complete). Extremely wide and menacingly low, it seems to loom over whatever patch of ground its parked on, giving off an air of magnificent malevolence.

It looks fantastic when followed from behind, but it’s the front view - featuring the thinnest headlight design ever seen on a BMW for a sleek, Iron Man-like face - that really grabs your attention.

Proportion, poise and big old 20-inch wheels give it plenty of presence, while the way the glasshouse tucks in at the rear only magnifies its powerful hips.

BMW has also thrown plenty of design flair at the interior, where you’ll find the unusual yet fabulous-feeling glass gear lever (there’s more of this sparkly, cut-crystal-like stuff on the volume knob, Start button and iDrive controller).

Not only does it feel truly unique and expensive in your hand, but it has an 8 buried beneath it, which shifts and shimmers as you try and see it through the many angles of the glass.

Elsewhere, the cabin is swathed in merino leather and feels undeniably classy, with a touch of modernity via its big screen, but it’s still not quite as beautiful as the cockpit you’d find in an Audi of a similar price. Close, but not quite.

Hallelujah! The unloved folding hardtop is history and fabric is back in fashion in a BMW 3/4 Series-based convertible for the first time since the demise of the E46 convertible in 2006.

It improves the proportions and aesthetics out of sight while remaining superbly insulated. It’s also 40 per cent lighter to boot while liberating 80 litres of extra luggage space.

The roof requires just 18 seconds to drop away or erect again, and can be done so at speeds of up to 50km/h. And it looks great, with a taut fit that suits the BMW’s lithe lines to a tee. With all four windows dropped, it also does a fab impression of an American-style pillarless hardtop.

Roof up or down, the M4’s muscular styling has a tense sparseness to it that means business, reinforced by that oversized, M-specific kidney grille treatment that, admittedly, isn’t as divisive in real life. The smiley LED light wave out back also brings a friendlier tone, harmonising handsomely with the rest of the car.

This is probably the best-looking BMW convertible since the beautiful E46 era.

At the very least, you’d have to say the 8 Series is fit for purpose. The seats are hugely comfortable for long journeys, so that’s practical, there’s a handy tray for your phone, where it will be wirelessly charged, and there are two cupholders in front of that, and storage for bottles in the doors.

No human larger than primary school age will ever sit in the back, so there’s not a lot going on back there.

In terms of boot space, it’s reasonably capacious at 420 litres, or 350 litres for the Convertible.

The M4 Convertible is not a paragon of space efficiency, given its footprint.

At nearly 4.8 metres long and 1.9m wide, the M4 Convertible casts a sizeable shadow on the road, which only really pays dividends for front-seat occupants inside.

Ours was fitted with a very handsome pair of $7500, two-tone M Carbon bucket seats up front, a sort of futuristic tombstone design with a fixed headrest that looks like they were created by and for Stormtroopers; they do provide all the electronic adjustability one would need in terms of fore/aft, up/down and lumbar support movement.

But, unless you really need their g-force-bracing support and love their outrageous appearance, they are monumentally obstructive to effortless entry/egress and overall hip comfort if you don’t possess a gymnast’s physique. In fact, at times, they can feel downright torturous, especially in the gusset area due to the pointless (ironically) hard central bulge bit. The standard front seat set-up is perfectly fine, offering all the comfort and support expected in a luxury convertible, with the added bonus of headrest adjustability.

As with all G20/G80 generation 3/4 Series, the M4’s interior is a welcome return to form for BMW, from the excellent driving position and superb build quality, to thoughtful switchgear placement, brilliant ventilation and ample storage. And iDrive is probably the best and most intuitive multimedia system out there, too, needing no special skill or distraction once mastered.

A quick note about the instrumentation. The 4 Series design digital readouts are prettier than the standard 3 Series' ugly standard screen that looks ex-Honda Civic. This one offers alternative views and is easy to read at a glance. But it still makes us pine for good old analogue dials. Remember when BMWs were the world leaders in dial design?

Some familiarisation is also required to figure out the M part of the M4, including the various driving and performance modes; they’re divided into Road, Sport and Track settings. Yet, thankfully, they’re all far simpler to get your head round than before, which required too much fiddly concentration, since – once quickly learnt – everything is possible with eyes-on-the-road promptness. A new M Mode button offers pre-determined shortcuts to whichever drive combinations are desired.

The roof is well insulated, meaning that previous-gen folding hardtop-owning prospective buyers shouldn’t be too sad about the fabric above their heads. On the go, front occupants can enjoy a variety of configurations, starting with snug coupe-style cosiness and security, moving to cool pillarless hardtop-style windows-only down cruising, to the full top-down convertible glory. The latter also brings minimal buffeting at speed unless you’re stuck out in the back. Roof-up vision isn't brilliant, though.

Strangely, with the M Carbon bucket seat options ticked, it’s actually easier for some people to get into the back than the front. Pulling a strap sees the front bucket seats (slowly) whir as far forward as possible to allow sufficient room for people to clamber onto the rear seats.

Once sat, it’s clear that longer-legged people will struggle. Knee room is OK (especially if the front occupants are feeling sympathetic by moving their seats forward), there’s surprisingly adequate head room for your 178cm tester when slightly slouched, big feet can be tucked beneath the front seats and scalps never have to touch the rear glass thankfully.

And at least BMW has tried to make life back there comfier for smaller people, due to rear-facing air vents with climate and directional control, two USB-C ports, a pair of cupholders, a centre armrest and some handy storage. The materials are of a high quality construction, too.

However, the fixed back rest is far too upright, the knees-up posture quickly gets tiresome, the cushion is firm and you’re sat on a slight angle pointing outwards. Claustrophobics won't be too happy either. Annoyingly there aren’t side window buttons either, meaning only the driver can lower or raise them. The two-seater back seat is best saved for short trips or kids.

Happily, once the roof is dropped, the hemmed-in feel vanishes, there’s not too much wind intrusion or buffeting with the side windows up and there’s a sense of shared freedom that only a four-seater convertible can bring. Going the full drop-top experience will ruffle more than hairdos at freeway speeds, though. An optional wind deflector can fix that issue for front-seat occupants, but it goes over the back seats, turning the M4 into a two-seater ragtop.

Further back, the 300-litre boot isn’t accessible from the cabin, meaning you can’t put much inside at all. BMW fits a hinged flap that needs to be down for the roof to work since it cordons off the roof storage part of the boot when folded in; when lifted, there’s a useful amount of space for luggage, and it’s a handy rectangular shape instead of an L-shaped slot, but obviously at the cost of convertible driving. You can’t have both.

Note that, compared to the previous folding-hardtop M4, this boot is some 80L larger. 

There’s only one M4 Convertible available, in Competition M xDrive guise, and it’s not lacking for much.

We’re looking at a 375kW/650Nm 3.0-litre twin-turbo in-line petrol six-powered four-seater AWD ragtop capable of 0-100km/ in 3.7 seconds, on the way to either a 250km/h or optional 280km/h top speed, if your wallet allows. All from $176,900 before on-road costs. BMW’s serious here.

Standard features include an active M differential, adaptive suspension with auto levelling, an M Compound Brake package and selectable driving modes, underlining the M4's driver focus.

You'll also find leather upholstery, head-up display, adaptive cruise control with full stop/go functionality, automatic parking assist, a surround-view camera, a lap timer and “drift analyser”, paddle shifters, wireless smartphone integration including Apple CarPlay/Android Auto connectivity, emergency services access, three-zone climate control, electric front seats with memory, front seat heaters, ‘air collar’ neck warmer, keyless entry/start with BMW Digital Key, key fob control for windows, roof and boot opening, split-fold rear backrest, M carbon fibre trim, leather steering wheel, a 12.3-inch instrument display, a 10.2-inch control display, 16-speaker Harman/Kardon surround-sound audio system, digital radio, MP3 player, cloud-based satellite navigation, trip computer, wireless charging, ‘Hey, BMW’ assistant, outside connected services assistance, ambient lighting, BMW LED Laserlight auto high beams with active cornering and light sensitivity, rain-sensing wipers, electric heated/folding exterior mirrors, tyre pressure monitors, 19-inch front/20-inch rear wheels/tyres and a tyre repair kit.

Taking care of safety are six airbags, forward collision warning, Autonomous Emergency Braking (AEB) front and rear, with front/rear cross traffic alert, lane departure warning with passive steer assist, lane keep with active assist, blind spot monitor, 360-degree view cameras, parking assist, parking sensors, anti-lock brakes with electronic brake-force distribution and brake assist, stability control, traction control and corner braking, among other features. More details in the safety section below.

Our BMW also included three options that detracted from the M4’s comfort and/or taste: $5000 Frozen Portimao Blue paintwork, $7500 M carbon bucket seats and $8500 M Carbon exterior package, upping the total unnecessarily to $197,900 before ORC.

Rivals in the 2+2-seater ragtop arena are few and far between. With no Audi RS5 Cabriolet in existence, Audi only has the S5 Cabriolet from $126,200, but that’s up against BMW’s M440i Convertible from $135,900. There’s more parity with the ageing Mercedes-AMG C 63S Cabrio from $202,177 and softer Lexus LC 500 Convertible from $213,877, while the cheapest Porsche 911 Carrera Cabrio will set you back a cool $262,900.

Seen in that light, it’s fair to say the standard M4 Competition xDrive is in a league of its own – particularly when you factor in the BMW’s ability to more-or-less equal and even exceed the others at their own game. And that’s something the previous version could not achieve.

So, that’s a surprising yes for value.

Truly, there is one impressive engine sitting under that big, hulking bonnet. The M-fettled 4.4-litre V8 has two turbochargers located inside the V of the block for “immediacy of response”, and they certainly deliver that.

Peak power of 390kW is delivered between 5500rpm and 6000rpm while its hefty 750Nm of torque is on song, for effortless overtaking, from 1800rpm all the way to 4600rpm.

Looking at those rev figures it’s clear to see that you are initially launched by a huge wave of torque and then, while you’re still drawing breath, the power really kicks in. 

All that grunt equates to 0 to 100km/h in just 3.7 seconds, which is very fast indeed, and you also get to enjoy a growly, guttural soundtrack, thanks to the standard Sport Exhaust.

The Convertible has the same engine with the same figures, but it’s slightly heavier and thus takes 3.9 seconds to hit the tonne. Which is still stupidly fast for this much car.

Here is a summary of Australian-market outputs and prices for the M3 and M4 convertible autos, with the prices in brackets being approximate inflation-adjusted figures for today.

1999 E36: 236kW/350Nm 3.2L in-line six-cylinder engine (I6), $152,000 ($266,000 in 2022); 2003 E46: 252kW/365Nm 3.2L I6, $158,000 ($240,000); 2008 E93: 309kW/400Nm 4.0L V8, $183,442 ($240,000); 2014 F83: 317kW/550Nm 3.0L twin-turbo I6, $178,430 ($202,000).  

In 2022, the G83 M4 Competition lives up to its name in more ways than one, with a 2993cc 3.0-litre double overhead cam direct-injection twin-turbo I6 known as the S58 series, which is itself derived from BMW’s B58 modular family of engines. Its 375kW is delivered at a lofty 6250rpm, while there’s a 650Nm plateau of torque between 2750rpm and 5500rpm.

A kerb weight of 1920kg means the M4’s power to weight ratio is an impressive 195.3kW/tonne, helping its published 0-100km/h time of 3.7s. For a few grand extra, the company will up the top speed by 30km/h, to 280km/h.

BMW says the engine includes cooling and oil supply systems designed for extreme lateral forces at high speeds, while the exhaust uses electrically controlled flaps for a more raucous noise.

Power is channelled to all four wheels continuously via an eight-speed M Steptronic transmission with a trio of shift programs. The AWD system features an active differential to better transmit torque to all four wheels, while drivers can choose one of three, progressively more rear-wheel drive (RWD) biased modes: 4WD, 4WD Sport and 2WD – the latter being a pure RWD set-up.

Other related changes the M4 boasts over regular 4 Series models include special stability and traction control tuning, a double-joint spring strut front axle with unique axle geometry and variable-ratio steering, a five-link rear axle featuring its own kinematics and elastokinematics, M-specific adaptive dampers, a configurable braking set-up according to feel and response, and forged M light-alloy 19-inch alloys up front and 20-inch items out back.

Choosing the AWD-only convertible over the equivalent AWD coupe adds 145kg (and 195kg compared to the RWD coupe), though this is partly offset in two ways over the preceding, folding-hardtop M4 Convertible: firstly, using the soft top drops weight by 80kg; and secondly, while the AWD system does add 50kg, it’s at a lower centre of gravity, thus naturally improving vehicle dynamics.

Which are electrifying, by the way.

Good luck ever matching these figures, with all that V8 temptation beneath your right foot, but the claimed number, at least, is 10.4 litres per 100km for the Coupe and 10.6 for the Convertible. During our launch drive we would have been absolutely nowhere near those figures.

We managed 12.1 litres per 100km in a mixture of urban, freeway and rural-road driving, including plenty of performance testing. This is a two-tonne M4 convertible capable of supercar speeds, after all. In that context, the economy is more than acceptable. No doubt the stop/start engine function (at idle) helps here.

For the record, the official combined-average claim for this Euro 6-rated BMW is 10.4L/100km, for a carbon dioxide emissions average of 237 grams/km. Thanks to a fuel tank that holds 59 litres of 98 RON premium unleaded petrol, it can manage an average of almost 570km between refills.

There is a sizeable distance between driving a small, lithe sports car that can sprint from 0 to 100km/h in a scorching 3.7 seconds, and then piloting something that feels as large, and louche, as a cruise ship that can do the same thing.

Accelerating in the M850i is an experience that can only be described as hilarious. There’s just so much mass attempting to move so quickly that it defies belief. The way the nose rears into the air, and the rear end seems to dip towards the ground, brings to mind a bucking bronco, although a feisty polo pony would probably be more appropriate.

It’s easy to see why this car is all-wheel drive rather than the traditional BMW rear-driven layout, because there’s just no way you could get all that grunt to the ground with two wheels, or not without some serious power oversteer issues.

For a car that weighs more than 1.8 tonnes, the 8 Series is surprisingly fluid and involving on winding stretches of road. It feels hunkered down and hammered into the road, which is less of a surprise, but the steering is so perfectly weighted and the power delivery so well calibrated that it really encourages you to push on, and rewards you sense of adventure with smile-widening pace.

It’s quite something to suggest of a car that costs a quarter of a million dollars, but the M850i actually exceeds your expectations in terms of driving joy. On paper, it looks like a straight-line bully, or merely a very grand grand tourer, and it does eat up the miles on a freeway with class and ease, but when you want to point it at a mountain pass, it excels there as well.

We drove the new 8 Series back to back with BMW’s also-new Z4, and what really stood out was not just the gulf in power and poise, but the huge difference in the ride/handling balance.

The M850i really can soak up the worst our roads can throw at it with aplomb, while still making you feel connected to the ground beneath you, and inspiring confidence, and its abilities really did make the Z4 feel very brittle and hard indeed.

To be fair, we didn’t get to throw this big luxo-barge at any sections of really sharp S-bends, or 35km/h corners, and no doubt it would be challenge for it to change direction quickly, but through fast sweepers it really does excel.

And as far as its grand-touring design brief, it absolutely nails it.

Marvellously.

Earlier, we said that the previous M4 (and some earlier M3 generations) never hit the dizzy heights the best like the E46 managed.

The reason why is bandwidth. Not WiFi bandwidth, but rather the newfound breadth of capability that the G83 model has acquired.

Yes, while even the slowest examples of previous M3s and M4s remained thrilling, with blisteringly potent acceleration accompanied by a soaring exhaust soundtrack, the post-E46 models seemed to become almost too obsessed with the pursuit of performance. Thunderous V8s and twin-turbo V6s are all good and well, especially when they provide explosive responses, but there’s more to sports cars than sheer bloody-minded speed.

More specifically, though the handling and roadholding were outstanding, the previous M4’s steering didn’t feel as connected or one with the driver, instead seeming a little remote and detached. Conversely, even with adaptive dampers on offer, the suspension (on Australian roads) lacked sufficient isolation from bumps and thumps, and so was never settled or calm. It was all too nervous and edgy, like a drug-addled athlete who’s indulged in too much partying.

Thankfully, the curse is broken with the latest iteration, even in the heaviest and slowest version like our M4 Convertible as tested, pushing out boundaries to thrilling effect once more.

With the newly-simplified and logically presented M performance modes only a push of a button away, the driver now no-longer has to concentrate on what setting they’re in, and instead just immerse themselves in the experience of accelerating, steering, cornering, braking and controlling this incredible sports convertible.

Tremendously strong in regular Road mode, the M4’s performance certainly lives up to the legend, stepping up into the supercar realm when Sport or Track are chosen, hunkering down as it thrusts towards the horizon with relentless speed and determination, accompanied by the gorgeous twin-turbo six’s revs as they soar towards the red line. The ultra-alert eight-speed auto’s operation is equally seamless, displaying uncanny intuition in its selection of the right ratio at exactly the right time.

These are all incremental improvements over what has come before. But what’s really changed is how rock-solid the BMW feels as it belts along at speed, magnetised to the motorway regardless of weather, its new AWD engineering keeping everything steady and planted. No more tetchiness to unnerve the driver.

Which makes the feel and fluency of the chassis even more remarkable, given that now all four wheels are driven. The very opposite of leaden or inert, the superbly weighted steering is instead light and alive in your palms, as you carve through corners with pin-point precision. Some might find it a bit too eager to change direction at first, but we reckon BMW has judged the balance just right. Its sheer agility is as life-affirming for driving enthusiasts as it is immersive. Bravo, BMW.

With so much grip and control, this is not to say that the driver can’t hang the M4’s tail out every-which-way, since the chassis set-up allows for progressive oversteer, even in Road mode, along with as much drifting as your courage allows where safe. As with the best sports cars, the M4 is as steerable from the seat of your pants as it is using the throttle.

Finally, there’s the M Adaptive chassis tune, that at long last broadens the M4’s repertoire from motorway grand tourer and rural-road blaster to city slicker and urban warrior, thanks to the suspension’s ability to better-absorb a much wider array of terrible road surfaces. Comfort now lives up to its name, with the ride – though still firm – no longer hard or crashy around town, ushering in a new level of civility that won’t fatigue or aggravate you or your occupants. We're so happy to report this progress.

One area where BMW might want to keep improving, though, is the abundance of road noise intrusion over certain coarse chip bitumen. While easily muffled by the sweet sounds of the twin-turbo six, banging audio system or dropping the roof, it now seems more obvious that the rest of the car has smartened up so much.

A small fly in an otherwise hugely satisfying ointment.

There is no specific crash-test data for the BMW G83 M4 Convertible.

However, tested in 2021, the G23 4 Series Convertible it’s based on (and tested in European-spec 320d guise) managed to score a five-star ANCAP rating, and performed strongly across each of the main disciplines – adult protection, child protection, vulnerable road-user and safety assist categories, achieving 96 per cent, 86%, 93% and 73% respectively.

Standard safety features includes six airbags (a driver’s knee airbag, dual frontal, side chest and head-protecting airbags for the first row and side chest protecting airbags for the second row), forward collision warning, Autonomous Emergency Braking (AEB) front and rear, with front/rear cross traffic alert, lane departure warning with passive steer assist, lane keep with active assist, blind spot monitor, 360-degree view cameras, parking assist, parking sensors, anti-lock brakes with electronic brake-force distribution and brake assist, stability control, traction control, corner braking and tyre-pressure monitors, BMW LED Laserlight auto high beams with active cornering and light sensitivity and rain-sensing wipers.

The AEB technology is rated for City, Interurban and Vulnerable Road User, according to ANCAP, and works between 5km/h and 210km/h in daytime and nighttime conditions.

There are also two ISOFIX points as well as two top tethers for straps in the rear seats.

BMW is sticking with its not-very-industry-leading three-year, unlimited-kilometre warranty, and says its customers are happy with that, rather than the five- or seven-year warranties some other companies offer. When you’re paying this much for a car, it seems a trifle mean, frankly.

Like all modern BMWs, the servicing requirements for your M850i are controlled by the Condition Based Servicing (CBS) system, which means that “advanced algorithms monitor and calculate the conditions in which a vehicle is used, including mileage, time elapsed since its last service, fuel consumption and how a vehicle is driven”. 

That information allows the car to decide for itself when an annual vehicle inspection or oil service is due.

BMW offers two fixed-price servicing plans, under its BMW Service Inclusive (BSI), which is available in two packages: Basic - $2,290 for five years/80,000km or $5,170 for Plus.

We feel here is where the company drops the ball.

Trailing all of its main luxury car rivals (except Porsche) by two years, BMW only offers a three-year/unlimited kilometre warranty, as well as three years of roadside assistance.

BMW says its vehicles’ servicing is condition-based, depending on how they’re driven and other factors, with a dash warning appearing to let the driver/owner know when it’s time. We advise servicing your M4 annually or at every 10,000km, just to be sure.

No capped-price servicing system is offered. However, as long as the first one is paid for before the first service on a new vehicle, the ‘BMW Service Inclusive Basic packages’ is available at extra cost, covering scheduled servicing for three years/40,000km or five years/80,000km.

No prices are published for M models like the M4, but a normal 4 Series costs from $1800 for the five-year/80.000km package. You can bet an M4’s will cost more.