BMW M4 vs Porsche 718

What's the difference?

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.

If this is to be the end of the 718 as we know it, then it is an end to be remembered. Porsche has produced something special in the Spyder RS, a sports car that can compete with the 911 on any stretch of road - which is something so few cars can claim. The focus on performance has driven the entire concept of the car, but all the elements work in harmony, with form and function coming together.

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.

As the pinnacle of not only the current 718 range, but potentially the entire combustion engine era of the Boxster, Porsche has pulled out all the stops for the Spyder RS.

This includes major changes to the design, but none are purely for aesthetic reasons and instead are driven by the search for performance; and the fact they make the 718 look tougher, meaner and more purposeful than ever before is just a bonus.

It’s a comprehensive redesign that starts at the bumper with a new front lip spoiler to enhance downforce. Then there’s a pair of NACA ducts on the lightweight bonnet to improve brake cooling without compromising aerodynamic drag. The lightweight front fenders include wheel arch vents to stop any potential for front-end lift at high speeds.

And the fenders aren’t the only component that’s gone on a diet, there’s a lighter exhaust, lighter wheels, lighter bonnet, lighter roof, lighter door panels and even lighter carpets on the inside. All up, the Spyder RS tips the scales at 1400kg, which is 40kg lighter than a standard 718 Boxster.

If it’s still not light enough, you can opt for the optional 'Weissach Package' (which was fitted to our test car), which brings even lighter 20-inch forged magnesium wheels and carbon-fibre reinforced plastic for a range of parts including the front luggage compartment, rollover bars and ducktail spoiler on the Gurney flap – plus some cosmetic enhancements.

And we still haven’t even touched on the biggest design change yet - the rear half of the car. Starting with the roof, which Porsche actually calls a ‘sunshield’ and ‘weather guard’ because it’s a stripped down version of what the brand usually uses, to save weight and let the glorious engine noise into the cabin uninterrupted.

But it’s also necessary because the entire rear engine cover has been redesigned to accommodate the larger engine that Porsche has installed in the Spyder RS, a 4.0-litre six-cylinder instead of the usual turbocharged four-cylinder ‘boxer’ engines.

While the Spyder RS looks great with the roof/sunshield on or off, frankly the removal process is much too complicated and requires repeated viewings of a YouTube tutorial to still get it wrong.

While owners will (likely) eventually get the hang of it, it will always be a clunky and awkward process and that’s just the price of being so focused on performance, which you can accept or not.

Inside that ethos of performance over practicality continues, with sports seats, an Alcantara-wrapped steering wheel and even the previously mentioned lightweight carpet floor mats.

It’s a purposeful, rather than luxurious, cabin, but that perfectly suits the nature of the Spyder RS. Our test drive included several long stretches behind the wheel and at no stage did it feel uncomfortable or impractical, despite its stripped-down design.

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. 

One area where the 718 range is starting to show its age quite dramatically is the in-car technology. While Porsche’s native system is relatively user-friendly, the lack of wireless Apple CarPlay or Android Auto in any capacity is deeply out-dated; and was frustrating for this Android using reviewer.

Given the age of the current 718 platform, and the impending arrival of the new model, it’s understandable that the multimedia system didn’t get an overhaul, but for a $350K car it does feel a bit behind the times.

In practical terms the Spyder RS is a bit of a struggle if you plan to go away with it. We managed to get a small suitcase and backpack in the under bonnet storage, but that was at capacity. While the addition of the larger engine removes any meaningful rear storage space.

The bad news is, the Spyder RS costs just over $200,000 more than the entry-level 718 Boxster, which is not a small sum of money. The good news is, for that $200K, Porsche has overhauled the 718 from nose-to-tail and enhanced it in nearly every aspect.

There’s a raft of mechanical changes that we’ll get to later on, to help justify the $334,200, plus on-road costs, asking price, but from a specification perspective there are some notable inclusions. 

For starters it comes with the 'Porsche Communication Management' (PCM) multimedia system, which includes in-built navigation and Bluetooth connectivity, as well as a 110-watt sound system.

But Australian delivered cars get an even higher level of standard equipment than other countries, with LED headlights including 'Porsche Dynamic Light System' (PDLS), cruise control, digital radio, rear 'ParkAssist' with reversing camera, 'Light Design Package', tyre fit set and windscreen with grey top tint, plus a no-cost optional Bose Surround Sound System all included.

It may be $200K more than 718 but compared to a 911, it actually makes a pretty compelling value argument. A 911 Cabriolet Carrera S starts at $342,700 (plus on-road costs), making that Spyder RS $8500 cheaper and a genuine alternative to its ‘big brother’.

Then, when you compare it against similar mid-engine European sports cars, such as the Maserati MC20 (from $510,000) or McLaren Artura (from $477,310) the Porsche looks like a bargain; relatively speaking, of course.

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.

The key stat for the engine is the cylinder count. Gone are the four cylinders and instead it’s a return to Porsche’s iconic flat-six.

Specifically, the same 4.0-litre six that Porsche uses in its 911 GT3, which is a lot of engine to squeeze into the middle of this lightened sports convertible.

In order to keep the 718 in its place (beneath the 911), Porsche has slightly detuned the engine, so it makes 368kW/450Nm (compared to 375kW/460Nm in the 911 GT3), but the German brand has never worried about a kilowatt contest and instead prefers to focus on driveability and the other elements that make a drive great.

To that end the combination of air-intakes next to the headrests and the lightweight stainless steel exhaust (which gets titanium tips on the Weissach Package) helps the Spyder RS sound like a Carrera Cup racing car when you really wind it up to its 9000rpm redline.

Not that the performance isn’t spectacular, though, with Porsche claiming it takes the Spyder RS just 3.4 seconds to run 0-100km/h, only 10.9 seconds to get from 0-200km/h and will hit a top speed of 308km/h.

The engine is paired to a seven-speed dual-clutch auto transmission (or PDK in Porsche-speak) that the company claims has “short-ratios”, but with peak power not hitting until 8400rpm and peak torque from 6750rpm, you don’t have to rush the ratio changes.

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.

Porsche says the 4.0-litre engine in the Spyder RS uses 13.0L/100km, which is a big number for what is a relatively small car. But that engine is highly-tuned and built for performance not efficiency, so it’s something owners will need to accept.

Our test drive included some long highway stretches, as well as some spirited driving and urban commuting, so a good mix across all conditions, and we saw consistent returns around the 15-16L/100km range.

It has a 64-litre tank, which means a theoretical driving range of around 490km, assuming you can hit the official claim.

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.

I’m only giving it a nine out of 10 because perfection is hard for any car to achieve, but the 718 Spyder RS goes as close as any car I’ve driven. This is a masterpiece of modern sports car design, pushing the 718 closer to the 911 than ever before, which is something Porsche has clearly tried to avoid so as to not tarnish the image of its flagship.

But with the 911’s 4.0-litre flat-six in the middle of the 718, plus its more compact dimensions, the lightweight nature of the Spyder RS and the raft of chassis and handling enhancements, this really does leave you questioning ‘do I really need a 911?’

The steering is fantastically direct, the chassis responds to every input with precision and feedback and the braking is strong and consistent. Which helps because that engine is so good it launches you with ferocity and a glorious noise (as good as anything on the market today) whenever you squeeze down on the accelerator.

The highest praise I can give the Spyder RS is not that it was a dream to drive on winding, challenging roads, but that it was just as enjoyable on a trip to the shops or cruising down the freeway. Any drive in this car is a genuine pleasure.

This is another area where the 718 is showing its vintage, with very little in the way of active safety features. There’s the required stability control, as well as airbags for driver and passenger, plus the previously mentioned reversing camera. But that’s it, there’s no autonomous emergency braking, no lane-keeping assist or even adaptive cruise control.

While that may sound shocking to some, there’s never a moment where you feel unsafe in the 718. It feels incredibly stable and responsive on the road, as the onus falls back upon the driver to pay attention and make smart choices.

There’s no ANCAP rating for the 718, or any Porsche, so it is a question of putting your faith into Porsche’s in-house safety measures.

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.

It’s difficult to give the Spyder RS a clear score here because Porsche is cagey on the details. The public dealer websites indicate annual oil maintenance is required, with additional servicing every two years or 15,000km. 

How much that will cost is unclear, as despite the rest of the 718 range having publicly available prices, there were no such details for the Spyder RS (or even its Cayman sibling, the GT4 RS).

For reference, the 'standard' 718 requires oil maintenance ($895) for the first annual service and an inspection ($1500) the year after. Those costs continue to alternate annually out to eight years/120,000km.