BMW M8 vs BMW Z4

What's the difference?

With dramatic looks, a luxurious spec, and impeccable quality, the BMW M8 Competition Gran Coupe remains supremely well controlled as it delivers eye-widening performance and amazing dynamics. But there’s an ‘edge’ to the experience you need to be ready for. If I was determined to head for the Aussie ‘fast lane’ in a BMW 8 Series Gran Coupe I’d opt for the M850i and pocket a lazy $71K (enough for a cheeky M235i Gran Coupe to add to your collection).

The Z4 didn’t make me feel like Peirce Brosnan’s 007. It’s way too serious – a proper gritty reboot. Maybe it’s meant for Daniel Craig. Either way, its brave design makes it one of the best-looking BMWs of recent memory, and it’s a tech- and comfort-fest that the Bavarian automaker should be proud of. I just wish it was a smidge more fun behind the wheel.

Want to start a vigorous car enthusiast discussion (more a verbal punch-up)? Simply ask whether a four-door car can be a coupe.

Traditionally, the answer is no, but over time numerous automotive brands have applied that description to cars with more than two doors, including SUVs!

So, here we are. A four-door ‘Gran Coupe’, and the M8 Competition version retains the smoothly tapering turret and frameless side glass that help give selected BMW four-door models the same swoopy, coupe look.

At close to 4.9m long, a fraction over 1.9m wide, and under 1.4m high, the BMW 8 Series Gran Coupe has a firmly planted, low-slung, wide-track stance. Always a subjective call, but I for one, think it looks stunning, especially in our test car’s ‘Frozen Brilliant White’ matt paint finish.

In an era of comically oversized BMW grilles, things are relatively under control here, with a bright black finish applied to that ‘kidney grille’, as well as the huge front bumper air intakes, front splitter, front fender vents, exterior mirrors, window surrounds, 20-inch rims, lip spoiler on the boot, rear valance panel (incorporating a functional diffuser), and quad exhaust tips. The roof’s black, too, but that’s because it’s made of carbon-fibre.

Overall the M8 Competition Gran Coupe is a compelling combination of strong, confident character lines along the bonnet and lower flanks, with tightly wrapped curves following the high hip line, and more organically irregular, yet distinctly BMW shapes in the head- and tail-lights. 

The interior is a beautifully balanced design with a broad centre console sweeping up to the middle of the dash and wrapping around to focus on the driver, in typical BMW fashion.

 The multi-adjustable sports front seats are immaculate, with high-end quilting in the centre section matching a similar treatment in the doors. The dark grey (full) leather trim is offset by carbon and brushed metal trim elements for a cool, calm and focused feel.

Crack the bonnet open and a spectacular ‘BMW M Power’ carbon cover dressing the top of the engine is guaranteed to impress friends and family.

The Z4 is a sight to behold. It’s brave, especially for a BMW, it even betrays the brand’s strongest styling pillars, making its own way with its more horizontal grille design, flat body and curved out rear.

It’s more than that, though. In black, this car looks sinister, brooding. The more you look at it, the more you notice tiny details - the scooped-out sides, or the way the entire rear seems to flick up into the integrated spoiler. I couldn’t get enough of staring at it – it manages to look even better with the roof down.

That’s probably when it hit me. To my eyes, at least, this is the most stunning BMW in years. Sure, the X7 is a sight to behold due to its sheer dimensions and borderline offensive grille, but the Z4 is the opposite. It’s subtle, it hides its details away in its silhouette.

It’s designer, Calvin Luk (an Australian no less), was inspired at least in part by the Z8 – another Brosnan bond car – and you can see the Fisker design reflected in the Z4’s low, flat grille and almost bulbous rear.

Inside, sadly, the Z4’s strong design doesn’t quite play out. There’s no wily Fisker touches here, just a standard set of BMW switchgear. While it all works well, it just dumbs down the Z4’s character.

The big, chunky steering wheel in particular is a let-down. It’s the same wheel that sits in the brand’s X5 SUV, and it feels right there, but not here in a convertible where you’re so close to the ground. A smaller wheel would not only suit this car better, it would make it feel just a smidge more alive. I miss the three-spoke M sport wheel from previous-generation BMW cars.

I do like the dash, which is seemly carved from rhomboid shapes - a theme that rolls into the doors, screens, and vents elegantly. I’m normally not a fan of gloss plastics and chrome touches, but in the Z4 they’re all tastefully applied.

The seats, too, are lovely. I’m not sure about the contrast bright-red leather our car came with, but they’re nice and close to the ground and have excellent trim that you seem to sink into just enough to be comfortable and sporty all at once.

It’s a slick place to be, I just wish it felt less like you were at the helm of an SUV and more like you were driving something that looks this damn good.

Of the M8 Competition Gran Coupe’s 4867mm overall length, 2827 of it sits between the front and rear axles, which is a pretty healthy wheelbase for a car this size (and 200mm more than the 8 Series two-door coupe).

Space up front is generous, and one upside of a four-door, rather than two-door coupe, is you’re not struggling quite so much for space to get in and out when parked next to other cars.

Once inside, there’s plenty of storage up front, with a large lidded box/armrest between the front seats, twin cupholders in the centre console, as well as another covered area for wireless phone charging and extra bits and pieces in front of that. Long door pockets provide space for bottles, and the glove box is a decent size. There’s 12V power as well as USB sockets for media connection, with charging outlets in support.

At first glance you’d swear the rear seat was designed as a two-seater only, but when push (literally) comes to shove a centre passenger can squeeze in, legs straddling the rear console.

In terms of legroom, at 183cm (6’0”) I could sit behind the driver’s seat set for my position with knee room to spare, but headroom is another matter, with my noggin making solid contact with the soft Alcantara headlining. It’s the price you pay for this car’s racy profile.

There’s a neatly trimmed storage box and two cupholders in the fold-down centre armrest, plus door pockets with enough room for small bottles. The rear console houses dual climate controls, twin USB power sockets, and a small oddments tray, as well as buttons for the optional rear seat heating fitted to our test car ($900).

The 440-litre boot is a bit like the car itself - long and wide, but not very high. The rear seat split-folds 40/20/40 if you need more space, and the boot lid is automatic with a hands free function. But don’t bother looking for a spare of any description, a tyre repair kit is your only option.

The Z4 is a convertible, so it’s naturally compromised on space. As far as convertibles go though, you’ll be hard pressed to find one you can fit more stuff into.

The Z4 is wide - the same width, in fact, as a 5 Series - and this carries into the cabin. There are only two seats, but those seats are wide, and occupants will find themselves with luxurious amounts of airspace for their arms, as well as excellent leather-trimmed and padded surfaces for landing elbows on.

Legroom is also great, as the seats have a surprising amount of rail-travel on them, so that even taller folk won’t struggle to fit their limbs in.

A genuinely impressive characteristic of the Z4 is much head room there it is. Despite its low-slung looks from the outside, the roof towers over my 182cm tall head when I’m inside, so this isn’t one of those convertibles that feels like braking too hard might simply decapitate those above six-foot tall.

In terms of storage areas you get some long but shallow trenches in the doors, a bay with connection ports and a Qi wireless charging pad under the air-conditioning controls, a glovebox (hey, not all convertibles have them) and a trick centre console that houses two deep cupholders inside.

There’s also a netted shelf behind the seats that could fit small bags, and given the length of the cabin, you could even fit laptops and the like behind the seats provided you haven’t used the full extent of the seat’s rearward movement.

The boot is deep, wide and long for a drop-top, and offers a total of 281-litres which is more than some popular hatchbacks. It even offers tie-down points and netting either side. To top it off, the fabric roof folds away into its own compartment, so the boot space is unaffected if you choose to drop the lid.

For a convertible – the Z4 is a practicality wizard.

The Z4 isn’t cheap, but it plays in a field of expensive Deutsche drop-tops. Our car was the mid-spec 30i which comes in at an MSRP of $104,900 (before on-road costs).

For that you’ll get a more highly tuned version of the base 20i’s four-cylinder turbocharged engine, producing 190kW/400Nm, 19-inch alloy wheels, M Sport brakes, Adaptive M suspension, and adaptive LED headlights.

That’s on top of the already impressively-specified 20i’s kit which includes dual 10.25-inch screens – one for the multimedia functions, the other as a digital dashboard, a head-up display, full Vernasca leather interior trim, auto-dimming rearview mirror, power adjustable and heated front seats with memory function, dual-zone climate control, 10-speaker 205W stereo, a Qi wireless charging pad, and adaptive cruise control as part of a marginally upgraded safety package (more on that in the safety section).

It’s a pretty plush set of equipment, although a challenging value proposition as the almost-as-well-equipped 20i starts from $84,900, a full $20k cheaper.

Rivals for this 30i model? You’ve got the soon-to-be-discontinued Mercedes-Benz SLC300 ($102,500), all-wheel drive Audi TT S quattro ($105,661), and, at a stretch, the entry-level Porsche Boxster ($122,960).

Of course, being a premium European car, there is an extensive options list. Our car was fitted with the excellent and probably-worth-the-money M Sport differential ($2400), as well as the rudely priced M seat belts (literally just the M pattern embroidered in - $560!) and interior ambient lighting package (lovely, perhaps not worth $550).

The Z4 is only offered in five colours, three of which – including our car’s Black Sapphire – come at a cost of $2000. The red interior, surprisingly, is a no-cost option.

If you’re keeping track that brings the car you’re looking at here to $110,410. Not cheap, and it doesn’t have six-cylinders - but given its other attributes explored later in this review, the fact that it still manages to undercut an entry-level Boxster is actually reasonable.

The M8 Competition is powered by an all-alloy, 4.4-litre twin-turbo V8 engine, featuring direct-injection, as well as the latest version of BMW’s ‘Valvetronic’ variable valve timing and ‘Double-VANOS’ variable camshaft control, to produce 460kW (625hp) at 6000rpm, and 750Nm from 1800-5800rpm.

Designated ‘S63’, the engine’s two twin-scroll turbos are located, along with a cross-bank exhaust manifold, in the engine’s (90-degree) ‘hot vee.’ 

The idea is consistent transmission of exhaust energy to the turbos for improved response, with the reversal of usual practice completed by inlet manifolds positioned on the engine’s outer edges.

Drive goes to all four wheels via an eight-speed ‘M Steptronic’ (torque converter) auto transmission with ‘Drivelogic’, and dedicated oil cooling, as well as BMW’s ‘xDrive’ all-wheel drive system.

The xDrive set-up is built around a central transfer case housing an electronically-controlled, variable multi-plate clutch, with front to rear drive distribution set to a default 40:60 split.

The system monitors multiple inputs including, wheel speed (and slip), acceleration and steering angle, and is able to vary the ratio up to 100 per cent rear thanks to the ‘Active M Differential.’ 

Welcome to the age of ridiculously powered four-cylinder turbo engines. Despite a capacity of just 2.0-litres, the engine in the Z4 30i produces a whopping 190kW/400Nm.

That’s probably enough for a car this size. I’m keen to drive the six-cylinder, but surprisingly it seems to offer diminishing returns for extra cylinders offering a 60kW/100Nm power boost for an extra $20,000. Perhaps a six-cylinder is the way to go in a BMW, and given this car’s other seriously sporty attributes, it might be the only way to make it a bit more… fun. More on that in the driving section.

All Z4s are rear-wheel drive, using an eight-speed torque converter automatic. Sorry, no option for a manual this time around.

Claimed fuel economy for the combined (ADR 81/02 - urban, extra-urban) cycle is 10.4L/100km, the M8 Competition emitting 239g/km of CO2 in the process.

Despite the standard auto stop/start function, over a week-long combination of city, suburban, and freeway running we recorded a (dash-indicated) average of 15.6L/100km.

Pretty thirsty, but not outrageous when you consider this car’s performance potential, and the fact that (purely for research purposes) we exploited it regularly.

Recommended fuel is 98 RON premium unleaded, and you’ll need 68 litres of it to fill the tank. That equates to a range of 654km in line with the factory claim, and 436km using our real-world number as a guide.

It’s claimed that the Z4 will drink just 6.5 litres per 100 kilometres on the official combined cycle test, but I found that sticking my foot in occasionally resulted in a slightly more realistic sounding figure of 8.4L/100km.

That’s still a great fuel consumption number for a car like this, and perhaps one of the strongest benefits of having just four cylinders.

A discerning vehicle, the Z4 will drink nothing less than the best-quality 98RON unleaded to fill its 52-litre tank.

There’s something teutonically symmetrical about the way the M8 Competition Gran Coupe delivers its prodigious thrust.

Peak torque of no less than 750Nm is available from just 1800rpm, remaining on full song across a broad plateau all the way to 5800rpm. Just 200revs later (6000rpm) peak power of 460kW (625hp!) takes over to finish the job, with the rev ceiling sitting just over 7000rpm.

That’s enough to slingshot this 1885kg bruiser from 0-100km/h in 3.2 seconds, which is supercar fast. And the engine and exhaust noise produced by the 4.4-litre twin-turbo V8 during such rapid acceleration is suitably brutal, courtesy of electronically-controlled flaps in the system opening up. 

On a more civilised drive you can reduce the exhaust noise via an ‘M Sound Control’ button on the centre console.

The eight-speed auto is fast and positive, especially in manual mode, which dials up the fun via wheel-mounted paddles. And when it’s time to direct this car’s forward momentum into lateral movement BMW has brought in the engineering heavy artillery.

Despite its frameless door body structure the M8 Competition Gran Coupe feels solid as a rock thanks in no small part to its ‘Carbon Core’ construction, using four primary components - carbon-fibre-reinforced plastic (CFRP), aluminum, high-strength steel, and magnesium.

Then the ‘Adaptive M Suspension Professional’ (with active anti-roll stabilisation), the tricky xDrive continuously variable AWD system, and active M Sport diff combine to keep everything under control.

Suspension is a double wishbone front, five-link rear arrangement, with all key components in alloy to minimise unsprung weight. In concert with the electronic wizardry on-board, it helps keep the M8 buttoned down with only modest body roll in enthusiastic cornering, as the rear-biased AWD system seamlessly distributes drive to the axle and wheels that can make best use of it.

The price you’ll pay for the track-ready tune is in compromised ride comfort. Even in the ‘Comfort’ setting, the M8 Competition is firm, and feels corrugations and imperfections to a surprising degree.

An alignment of the BMW 8 Series planets left me with the keys to this car and the M850i Gran Coupe (also using the Carbon Core body) at the same time, and the difference between their softest settings is appreciable.

Also be aware that at 12.2m the M8 Gran Coupe’s turning circle is substantial, and it’s just as well all that camera, sensor and self-parking tech is available to help you guide this ship into port.

The M8’s electrically-assisted, variable-ratio steering features an ‘M’ specific calibration to deliver satisfying precision and good road feel. But in similar fashion to the ride a noticeable amount of unwelcome feedback comes through to the wheel.

The fat Pirelli P Zero rubber (275/35 fr / 285/35 rr) grips hard, and the monster brakes (ventilated all around, with 395mm rotors and six-piston calipers up front) wash off speed without fuss or fade.

But overall, you’ll have to live with a less refined drive when you sign on for the M8 Competition. Straight away it feels faster but lacks the M850i’s lighter touch. No matter which drive or suspension mode you select, responses are more aggressive and physical.

To fully explore and enjoy the M8 Competition’s abilities it feels like the race circuit is its most appropriate habitat. On the open road, the M850i is all the Gran Coupe you’re going to need.

A car that looks this good better live up to the promise behind the wheel, right?

For the most part, the 30i does, but it’s a victim of its own performance credentials and luxuriousness.

See, a drop-top should be fun-packed, you should feel close to the road, connected. Sadly, a combination Z4’s excellent suspension and not-so-excellent SUV-like interior separates you too much from the surface below.

An advantage, of course, is the refinement on offer. The Z4 is easily one of the quietest, most refined convertibles I’ve ever driven, but it’s a little too insulated.

I can’t help but feel like it’s all business and no pleasure. It feels a little more like I should be cruising to work on the autobahn and a little less like I should be flinging it around corners on a tight B-road.

It feels almost wrong to drive it in a T-shirt. It’s serious and doesn’t want you to mess around, it wants you to wear a suit and tie.

This grand-tourer style feel is one that will keep a lot of buyers in the premium space happy, but I’m of the opinion that BMW will have that segment well and truly covered by the new 8 Series. If the budget allows.

Regardless, the 30i’s four-cyl engine feels like any six-cylinder would have a few years ago. It’s got a surge to it in the straights that’s quite satisfying, and it responds via the exhaust with an angry tone that makes it feel a little more alive, especially with the roof down.

This feeling was all helped along by our car’s M active differential which simply won’t let the fat tyres at the rear slide unless you’ve got high-speeds and loads of tarmac to play with – for better or worse.

The Z4 also has ‘variable sport steering’ which reacts to the car’s speed and position of the wheels to adjust the input ratio. It’s good when you’re at speed, but the weight and response of the steering can make the Z4 feel bigger than it actually is at lower speeds. 

The suspension is firm, and can be a little bouncy over rough surfaces, but seems well suited to the Z4’s chassis.

Other than those notable characteristics you’ll find that the Z4 is wonderfully tuned in terms of its inputs, everything is slick and smooth, suited perfectly for long meandering drives.

Convertibles and safety don’t often fall in the same sentence, unless its one where a concerned relative is trying to convince you not to buy one.

In any case, the Z4 benefits from four airbags (dual front and dual side), as well as the expected electronic stability controls. That optional M Sport differential will have the added bonus of preventing any unexpected slip and slide at the rear.

On the active side the Z4 gets ‘Driving Assistant’ which includes forward collision warning (FCW), lane departure warning (LDW), rear cross traffic alert (RCTA), and rear collision warning. The 30i grade also gets 'active cruise control with stop & go' which allows for full auto emergency braking (AEB) with pedestrian and cyclist detection. Not on the spec sheet, but apparently present in the car I drove was some form of traffic sign recognition (TSR) and lane keep assist (LKAS).

A nice high-res reversing camera displayed on the massive touchscreen is a welcome standard addition.

Considering the meagre safety specification of most convertible cars, the Z4 30i shines with a half-way decent active safety suite. But you can forget ISOFIX child-seat anchor points. There aren't any. 

BMW offers a three year/unlimited km warranty, which is at least a couple of years off the mainstream market pace, and lagging other premium players like Mercedes-Benz and Genesis, both sitting at five years/unlimited km.

Roadside assistance is included for the duration of the warranty period, and the standard ‘Concierge Service’ provides everything from flight information, to global weather updates, and restaurant recommendations, from a real human.

Technically, service is ‘condition based’ with the car telling you when it’s time to hit the workshop, but you can use every 12 months/15,000km as a guide.

BMW Australia offers ‘Service Inclusive’ packages that require customers to pre-pay for servicing, allowing the cost to be covered off in finance or leasing packages and reducing the need for concern about paying for maintenance further down the track.

BMW says there are different packages available, from three to 10 years, or between 40,000 and 200,000km.

If recent quotes are anything to go by BMW is set to stick by its lacklustre three-year unlimited kilometre warranty, as it says its customers simply aren’t interested in five years (or longer) when it comes to warranty coverage.

It’s a shame, as even Volkswagen has upped its warranty to five years, and Mercedes has considered a 10-year coverage plan in the past.

In terms of servicing, there are two fixed-price plans available – the suspiciously cheap ‘Basic’ plan which comes at a cost of $1373 for five years (or $274.60 per year) and the more realistic-sounding ‘Plus’ which costs $3934 over five years (or $786.80 per year).

Like every other BMW, the Z4’s computer tells you when its service time: how often it needs maintenance will depend on how often – and how hard – you drive it.