BMW 8 Series vs Mercedes-Benz C63

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 Mercedes-AMG C 63 S Aero Edition is an absolute beast of a car, but it comes at a pretty hefty price. Yes you get a lot of performance, and the fact there are only 63 examples being made for Australia and New Zealand could be enough to get you to sign on the line. For me, though, if I was after a C 63, it’d have to be a wagon. It doesn’t need an Aero pack to look better.

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.

I’ve never been the biggest fan of the current C-Class Coupe’s styling. To me, it has always looked a little droopy, a little melted at the back. 

I have to say, the Aero Edition has changed my opinion somewhat, as the new graphic elements help lift it up a bit, visually raising its rear up like a stretching cat, tail in the air. I’m still not 100 per cent on it, but to my eye it’s better.

The carbon-fibre trim elements that have been added to the exterior certainly add some menace to the look, too, and I simply can’t help but constantly notice out of the corner of my eye the AMG pressing in the staggered, dished rims. At a glimpse, from a distance,  it looks like rim damage, but thankfully it’s not!

The staggered set-up does really add some width and mongrel to the look, as if it needed more, with its open maw lower bumper air dam, and the signature 'Panamericana' grille treatment which looks like an evil character out of a movie. If you know the one I’m talking about, let me know in the comments.

As much as the look matters when it’s parked in your driveway, it’s the cabin that arguably matters more, right? That’s where you spend your time, after all. Check out the interior images to see if you think it lives up to the exterior look.

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.

No two-door coupe is going to offer you the space and comfort of a sedan or wagon, that’s just a fact. But that only matters if you plan to actually use the rear seats. If you don’t, then the Coupe version of the C 63 S might be perfect for you.

Even so, I managed to (only just) squeeze myself between the seat and the door opening to slide into the rear row. This won’t be easily achieved by all attempters, especially on the driver’s side.

Let’s just say I probably looked like I was doing something very weird to the driver’s seat as I spider-manned my way in. 

The rear space is tight for someone my height (182cm/6’0”) behind their own driving position, with knees hard-up against the seat in front and not much headroom (my noggin’ was brushing the ceiling) or toe space (size 12s don’t fit so well) to speak of.

It’s certainly a selfish car. Or maybe it’d be fine for smaller kids. There are two spaces in the back, both with ISOFIX child seat anchors and top-tether points.

But there is storage in the back - cupholders and storage caddies either side of the seats, though the storage situation improves in the front zone, with bottle holders in the doors, cupholders between the seats, loose item storage under the media screen and a covered centre armrest bin, too.

The front cabin is a special looking place, with carbon-fibre abounding across the dash and nice trim on the doors. The AMG steering wheel is a sight to behold - it’s a flat-bottomed unit with carbon-fibre and Dinamica (that’s Benz talk for microsuede) trim: perfect for sapping sweat as you manhandle the C63 through the bends.

The seats are AMG Performance sports units up front, and the trim used is reserved for this model specifically: Nappa leather with yellow stripes. There are yellow details elsewhere, including on the rear seats, centre console and dash, and it certainly adds some visual excitement.

Media is controlled by a 10.25-inch display and Mercedes-Benz’s touchpad control system, but there is no touchscreen - rendering the Apple CarPlay and Android Auto smartphone mirroring technology somewhat tedious.

I’ve always had a gripe with screens that don’t allow touch but feature the tech that’s designed to transfer your phone’s screen to the media unit, and I can tell you the longer you spend twiddling the dial to get where you want to go, the more annoying it becomes.

The Burmester sound system has 13 speakers and is rather good, but I prefer the sound from the standard fit variable sports exhaust. So maybe that quibble with CarPlay isn’t that big a deal.

And if you just want to charge your phone, and there’s a second USB port up front, as well. Note: in non-Aero Edition C 63 models without the carbon-fibre interior pack, you also get Qi wireless phone charging, but it’s deleted from this variant and any model with the carbon pack.

The driver has a 12.3-inch digital info display to show where you are and what the car is up to, and there’s a head-up display as well. Yep, there’s standard sat nav with live traffic updates (and even live fuel price updates) - it’s just a shame the maps still look early 2000s-spec in 2D layout.

Cargo space is okay. The claimed cargo capacity or boot volume is 355 litres (VDA) with the rear seats in place. That’s small for a coupe of this size, and the shape of the boot (with a hump behind the rear seat) isn’t great as things do move around quite a bit.

But, thankfully, Mercedes has included its clever foldable storage box system under the boot floor - it goes where you might usually expect a spare wheel, but there isn’t one in this car. Instead you get Mercedes’ 'Tirefit' repair kit with an electric pump.

Look, I’m not likely to ever be in the position to say that a car that costs $188,600 plus on-road costs is “good value”, but to be honest, if you’re in that position, you’ll be getting plenty of car for your cash.

The Carbon Edition of the C 63 S Coupe adds $17,200 over the standard version of the high-performance two-door, but it adds a bunch of extras to help justify its price. A car like this is always going to be seen by some as a profligate purchase, right? You need to be able to justify spending an extra MG3’s worth of cash on this Edition. 

The noticeable exterior bits include an AMG Performance rear spoiler, a model specific front lip, rear diffuser, and side facings for the rear apron air vents. Carbon-fibre is used in the front apron A-wing, the side sill inserts, rear diffuser insert, rear spoiler and the side mirror casings. 

There’s more carbon-fibre inside the cabin, which we’ll cover off in the interior section. Other additions over the standard C 63 S Coupe include ceramic composite front brakes (402mm six-piston) and 360mm single-piston rear brakes, and there are “ultra-lightweight” AMG forged 'Matt Black' alloy wheels with 19-inch rims at the front and 20s at the rear. 

And in nice news, the car you see here has no optional extras fitted at all. The colour is 'Iridium Silver', one of only two options for this limited run model (the other available hue is Polar White, and both come at no extra cost).

Standard inclusions comprise leather interior trim, heated and electric adjustable front seats, dual-zone climate control, a 10.25-inch media screen with sat nav and smartphone mirroring, DAB radio, 13-speaker Burmester sound system, 12.3-inch digital driver info display, head-up display (HUD), ambient lighting, and performance items like active dynamic engine mounts, an adaptive AMG performance exhaust, a rear differential lock, and adaptive sports suspension.

Plus there’s a full-spec safety offering which we’ll cover in the section below.

Thinking about what cars compete with this one? There’s the Audi RS 5 Coupe (from $150,900), the Lexus RC F (from $136,636), and the BMW M4 Competition (from $167,829). So the C 63 S - which is already expensive comparatively - looks positively pricey in Aero Edition spec.

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.’ 

Open the shapely bonnet of the C 63 S and you’ll find a hand-assembled horsepower-monster engine with a printed name plaque to prove it.

The 4.0-litre twin-turbo V8 produces 375kW of power at 6250rpm, and 700Nm of torque from 2000-4500rpm. It runs a standard-fit nine-speed 'Speedshift MCT' (multi-clutch transmission) automatic, and it’s rear-wheel drive. And yes, that means it likes to boogie.

The claimed 0-100km/h time is just 3.9 seconds, and top speed is apparently pegged at 250km/h. Yeesh.

The name on the “Handcrafted by” plaque on this particular engine? Hat tip to you, Julian Rembold. This is quite a piece of work. 

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.

High numbers are what AMGs are about. Sadly that’s the case not only for performance outputs but also fuel consumption.

The official combined cycle fuel use claim for the C 63 S Coupe is 10.3 litres per 100 kilometres, and you need to fill it with 98RON premium unleaded fuel, too.

On test? Well, across a mix of different driving - urban, highway, back road and spirited stints - I saw an 'at the pump' return of 12.2L/100km, while the digital readout stated 12.0L/100km.

Given the performance on offer, and how much I took advantage of it during my week with the car, that’s not bad…

Fuel tank capacity is 66 litres. So go easy if you know there won’t be a fuel stop for a while.

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.

Just one word sprang to my mind when it comes to accurately describing the performance on offer from this car. The word is ‘brutal’.

Smash the accelerator and the power and torque on offer is enough to make your eyes feel like they’re not doing the right thing anymore. You get pushed back in your seat with a surge, and your ears are also rewarded with one of the best soundtracks in the automotive world. 

The engine builds pace with enormous intent, and the sound that comes from under the bonnet and out the back through the exhausts is addictive.

Yes, there is an active exhaust button which you have to press to make sure that you hear all that noise if you’re running around in 'Comfort' mode, and during my time with the car it was active the whole time.

I had some questions from neighbours over the week that I had this car about whether it was actually nice to live with on a day-to-day basis. And the answer is yes, if you put it in comfort mode it’s surprisingly amenable. 

The ride is really well sorted at pace despite having a bit of that trademark low-speed wobble that seems to afflict Mercedes products from A-Class through to the GLE SUV. But it wasn’t bad enough to really bother me, as most of my time was on highways and backroads.

The steering is direct and accurate. The only thing you need to be aware of is that you will lose traction at the rear axle when you put your foot down hard. And for the enthusiast that’s exactly what you want. 

I know I want to feel the thing squirm under throttle. It’s a rear-drive V8 coupe, after all. You want to feel like you’re a vein in its bicep muscle; you know, the one you see in a weightlifter’s arms – the one that wiggles around a lot. You want to have that. Right?

On the performance front it is exceptional. Twist the little dial on the wheel to 'Sport' or 'Sport+' (I didn’t sample 'Race' mode as I wasn’t at a racetrack), and everything feels like it’s had a protein shake.

Even so, in that mode it steers brilliantly, there's a nice feel through the wheel, and the ride, while stiff, controls the body brilliantly when you change directions. 

The transmission is very good, too. In Comfort mode it can take just a second or two at first to become accustomed to the idea that you want to drive aggressively.

But in Sport mode, or when you select the manual transmission mode using the trigger button on the steering wheel, you will certainly get the most out of the engine. That’s what I did when I was driving it in a ‘spirited’ manner.

If you are just after that high-end Coupe cruiser experience, it’s a relatively quiet car (provided the surface below isn’t the coarsest of coarse-chip bitumen), with enough luxuriousness to make it feel premium as well as sporty. That’s an important thing to consider, especially at this price point.

There is no applicable ANCAP crash test rating for the Mercedes C-Class Coupe, nor is there one for the C 63 specification. But when it was tested back 2014, the sedan scored five stars - as you’d expect.

It is comprehensively equipped in terms of safety technology, including auto emergency braking (AEB) with pedestrian and cyclist detection (from 7.0km/h to 70km/h) and it’s active for cars from 7.0km/h to 250km/h.

Plus there’s lane departure warning and active lane keeping assistance (from 60km/h to 200km/h), blind spot monitoring with 'Active Blind Spot Assist' that will stop you from veering into oncoming traffic, front and rear cross traffic alert, and adaptive cruise control (Distronic) with traffic jam assist.

The C 63 also features 'Route Based Speed Adaptation', which can adjust your speed based on where the car thinks you are on the map. Just note - if you’re driving through new tunnels that haven’t been flashed to your car’s nav (as happened to me in Sydney during my testing week) - then you could find the car dramatically braking for surface-level intersections. You can switch the system off, thankfully.

There are nine airbags fitted, and while you mightn’t use the rear seats much there are ISOFIX and top tether points for both positions (yes, only two).

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.

Mercedes-Benz is among the minority of luxury brands now offering a five-year/unlimited kilometre warranty plan - most still have three-year cover. So that’s a tick.

And the service intervals are pegged at 12 months/20,000km. Another tick.

Plus you can either pre-pay your service plan in three-year ($3800), four-year ($6000) or five-year ($6550) plans - roll it into the finance package, and it won’t hurt quite as much.

According to Mercedes, the three-year coverage option makes for a $900 discount over pay-as-you-go servicing.

Roadside assistance covers the five-year new car warranty period, too. So Mercedes seemingly takes good care of its customers. But if you have any concerns or questions over reliability, problems, issues or complaints about the C 63, check out our AMG C 63 problems page.