Gac M8 vs Mercedes-AMG S63

What's the difference?

The GAC M8 PHEV Luxury is a people mover that carves out a very specific niche, largely thanks to its plug-in hybrid powertrain and ambitious price point. It’s undeniably well specified and genuinely luxurious inside, but it never quite escapes its chauffeur-like identity as it's a vehicle built around passenger comfort rather than driver engagement.

Being a new brand in our market limits ownership appeal, at least for now. Where the M8 really impresses, though, is efficiency, and that alone may be enough to justify its unusual positioning.

Both of these vast vehicles are phenomenally comfortable - this is the kind of car that Mercedes does so well, and has done for decades. The S Class is rarely a disappointment but it's difficult to believe that such a big, heavy GT car can also dance the way the S63 does.

The S560 is far more weighted to being a GT - supremely comfortable with that active suspension, a growly, refined V8 and a cabin full of gadgets and comfort. The S63 is altogether more aggressive, to look at and to drive. Lopping the roof off both of them adds weight but, like any cruiser, also puts you out in the sun, the breeze and into your surroundings. Plus, in the case of the S63, you get more exhaust noise.

They're two very different cars and not just because of the engine. After all these years admiring it from afar, the S63 has delivered on my teenage expectations - fast, smooth and utterly mad.

The GAC M8’s design is… well, it’s out there. This isn’t a people mover that fades politely into the background. There are clear parallels with the Lexus LM, right down to the towering grille (complete with a vague hint of spindle shaping), which may well be the tallest grille I’ve encountered!

It’s a big unit, too, measuring 5212mm long, 1893mm wide and 1823mm high. The overall shape is sharply squared-off and prioritises presence over dynamism. It also comes standard with a full suite of LED exterior lighting.

The cabin claws back some design cred, though, as it’s downright plush with its semi-aniline two-tone leather upholstery - finished in a lush burgundy/black duo in our test vehicle. Accent panels vary between a diamond-design for the dashboard and doors, to suede soft-touchpoints and rose-gold inserts liberally scattered across the cabin. 

The only accent that doesn’t land is the large swathes of piano black on the centre console as it’s hard to keep clean.

There are some nice little surprises, too, like the fidget spinner-style crystal gear lever, which is surprisingly fun to fiddle with at traffic stops and two sunroofs with the rear fixed panel illuminating with internal ambient light.

Some of the finishes aren’t the best as there are joinery and door handles that don’t line up properly, which is surprisingly more annoying than you’d think once you notice it. But overall, the cabin feels well-considered and luxurious, even if the execution isn't always flawless. 

The S Class Coupe is obviously related to the sedan but manages a svelte appearance. Slimmer hipped and with a more Coke-bottle shape, the Coupe - if you squint a bit - has a bit of the classic old pagoda about it. Obviously you can't do pillars that slim anymore, but the glass roof takes away some of the visual weight inside and out. 

The cabriolet's roof is nicely integrated and looks good when it's  up, which isn't always the case.

They all look long, though. It's obvious to see why the cars all run on 20-inch wheels - anything smaller would look hilarious.

The cabin is a fairly sensible re-imagining of the E-Class. The big twin-screen layout of the dash and multimedia system seems a bit more at home here. The chintzy Burmester speakers in the doors let down an otherwise classy cabin, which steers clear of otiose vulgarity in looks and materials.

The front row has plenty of space and the seats feature heating and ventilation, making longer journeys comfortable. However, there’s no extendable under-knee support and only the driver gets lumbar adjustment. I’ve spent much of the week feeling like a chauffeur, as my husband and child insisted on sitting in the back!

The middle row is where the M8 really shines. The captain’s chairs are indulgent, offering full recline, footrests, heating, ventilation, and massage. Comfort is excellent, though the footrest extension limits space for the third row, and even at 168cm I found it a snug fit when fully reclined. Access is straightforward with grab handles and a low 143mm step-in height, though be mindful of kerbs as the doors aren’t forgiving when it comes to tall council strips.

The third row is one of the few that genuinely accommodates adults. Head- and legroom are ample, and the seats feel firm but comfortable, especially with the foldable armrest. Amenities aren't forgotten with four cupholders, two USB-A ports and directional air vents. Access requires sliding through the middle row, so it’s best if those seats are unoccupied, but otherwise it’s not too taxing.

Front-row storage is practical, with a mid-sized glove box, dual-opening middle console, cupholders and a clever phone cradle that integrates a wireless charging pad and cable routing for a tidy set-up. There’s also a USB-A and USB-C port and a 12-volt socket in the large shelf underneath the centre console.

The middle row enjoys three USB-A ports, a USB-C port, directional air vents, retractable sunblinds, tray tables (though not usable while driving) and climate control. Storage is decent, with six cupholders, one of which has heating and cooling, two map pockets, a pull-out drawer and a 220-volt AC outlet.

The 10.1-inch touchscreen multimedia system is serviceable but feels slightly small for the luxury segment. Graphics aren’t the sharpest, the layout isn’t always intuitive and some functions, like the heated steering wheel, require digging through menus. Wireless Apple CarPlay and Android Auto performed flawlessly throughout the week and the 12.3-inch digital instrument cluster is clear and well laid out.

Boot space is modest for a people mover, offering 280L with all rows in place which is enough for a small grocery run but not for a fully-loaded family outing. Folding the third row expands capacity to 1500L, though that leaves you with a four-seater. The loading height is low, which helps, but it has a tall lip which prevents it from being ideal for sitting on during tailgates or picnics. There’s a small underfloor compartment housing the tyre repair kit and a powered tailgate rounds out the package.

Well look, if you end up in the back of the S Coupe, it's not a riot of space. Obviously it has back seats (the SL doesn't even squeeze a jump seat into its considerable length) but they're for occasional, if luxurious, use.

The boot is a reasonably decent 400 litres, obviously the cabriolet loses a few litres with the roof folded. Front and rear passengers will both enjoy a pair of cupholders and the whopping long doors will each hold a bottle.

One thing hasn't changed in nearly 20 years - the S isn't cheap. Available in coupe and cabriolet, the S560 starts at $314,900 for the former and $336,900 for the latter. Step up to the S63 pair and you'll pay from $370,500 for the coupe and $399,900 for the cab. If you're super keen for something spectacular, the twin-turbo V12-powered S65 is available for between $508,900 and $520,500, and features Swarovski crystals in the headlights, for some reason.

As you can imagine, there's quite a bit to cover, so for both cars I'll stick to the edited highlights. The S560s roll on 20-inch alloys, has a 590-watt 13 speaker sound system, digital TV, auto parking, active cruise control, panoramic glass roof, Nappa leather, active seats and power-closing doors.

It also comes standard with a heating pack that not only heats the seats but the steering wheel and centre console. In the cabriolet you also get the 'Airscarf' neck heater.

Both cars also feature's Mercedes' Magic Body Control with curve function. More of that wacky feature later.

The S63 AMG is a step up in power, price and spec. One notable change from the S560 is the loss of 'Magic Body Control', which is replaced with mere air suspension. The 20-inch alloys are 10-spoke forged units, the brakes higher performance composites with red calipers, while an AMG sports exhaust brings the noise.

Naturally, both are swathed in high-quality leather and feature dual-zone climate control, heated and cooled electric seats that adjust in every direction, deep carpets, keyless entry and start, fully digital dashboards and just about every gadget to which you can point your imagination.

Entertainment and sat nav are via Mercedes' 'Comand' system, which is displayed on a massive 12.3-inch slab of glass at the top of the dashboard. The 13-speaker Burmester-branded system is predictably impressive and with Apple CarPlay and Android Auto, you only have to use the basic software for the radio or various car controls.

Both M8 grades share the same plug-in hybrid powertrain, pairing a 2.0L, four-cylinder, turbo-petrol engine with a single electric motor. Combined, they produce up to 274kW of power and 630Nm of torque which is impressive on paper, though it only manages 0‑100km/h in 8.8 seconds. Once the battery is depleted, outputs drop to a more modest 140kW/320Nm. Power is sent to the front wheels through a two-speed automatic transmission, and the M8 is not rated for towing.

To get the best performance from this type of set-up will require diligent recharging.

All four coupes and cabriolets ship with Daimler's formidable 4.0-litre twin-turbo V8. The S560 scores 345kW/700Nm to drive the rear wheels through Benz's own nine-speed automatic. With all of that available, the S560 will crack the ton in 4.6 seconds and make a wonderful racket on the way.

Moving on to the S63, the same engine delivers a massive 450kW/900Nm. The run from 0-100km/h is dispatched in just 3.5 seconds and if I thought the S560 made a good noise, the S63 with its standard sports exhaust makes a better one. Again, Mercedes' nine-speeder is along for the ride.

The M8 is equipped with a Type 2 CCS charging port, accepting up to 6.6kW on AC and 39kW on fast DC power. Being able to use a DC charger is a definite plus for a plug-in hybrid and you can charge the battery on this type of charger from zero to 80 per cent in around 30 minutes.

Its 25.57kWh lithium-ion battery is generous for a plug-in, delivering an electric-only range of up to 106km (WTLP). With a combined cycle (urban/extra-urban) fuel consumption figure of 6.1L/100km and a 56L fuel tank, the M8 offers an overall driving range of more than 1000km which is excellent for a vehicle of its size. As with any plug-in, regular charging is key to achieving these figures; over my week of driving, I averaged 6.2L/100km, which is very excellent.

GAC recommends a minimum 91 RON unleaded petrol.

The lower-powered 560 drinks 98RON at the rate of 8.5L/100km for the coupe and 9.9L/100km for the heavier cabriolet.

The S63 ups the ante with 9.9L/100km for the coupe and an identical 9.9L/100km for the cab.

Our launch program contained some...er...spirited driving, which would explain the mid to high-teens fuel figures.

Around town, the M8 delivers plenty of power and is whisper-quiet when running in electric mode. Once the battery depletes or you switch over to the petrol engine, that sense of instant oomph fades. Overtaking on hills is achievable, but even with an empty car it can feel a little underwhelming.

Steering is light, but the car feels solidly planted in most situations. Handling isn’t as dynamic as a Kia Carnival and the M8 can feel a touch ungainly through bends, though it’s more than manageable for everyday driving.

Ride comfort is high, especially for passengers, due to forgiving suspension and a cabin that doesn't let a whole lot of road or wind noise in. The M8 is a comfortable cruiser.

Visibility is surprisingly good for a 5.2m-long vehicle with minimal blind spots from the driver’s seat. The bonnet and dash, however, stretch further than they appear, which can make judging the nose a little tricky at first.

Ground clearance is only 143mm, so it’s easy to scrape the nose over speed bumps or when parking. The 360-degree camera system is decent, but manoeuvring into tight spaces still requires some care as it fills out a space. You also have to leave about a metre of clearance behind you if you want to open the tailgate.

Let's start with the S560. That smooth V8 rumble is all you'll ever hear if you just slot into drive and go for a leisurely spin. The nine-speed automatic continues to be a revelation to me - in the GLC63 it's good and here, once again, it's excellent, finding the right gear for the occasion and riding the fat torque curve. Other nine-speed autos are not very good at all.

The test route for the S560 played to the strengths of the car. It had some lovely winding roads, which brought the trick suspension into focus - the Magic Body Control with curve function is hilarious. While the active suspension works hard at all times to ensure the ride is smooth and drama free, the Curve mode (no, really) actually leans the car into corners.

Those of you who remember the video game Wipeout 2097 will be big fans of Curve mode. As you approach a corner, you turn the wheel and then the car leans into the bend. This isn't active damping reading the road, it's the outside suspension lifting the car and the inside lowering it, so the car feels like it's gliding, like a hovercar. It's wild but oddly calming. Mercedes reckons it's great for those who get car sick. As I didn't have my wife on hand to test this theory - she chucks at the first sign of a corner - I couldn't verify this claim. That will have to wait.

The S63 AMG is a completely different proposition. The air suspension is more than up to the job of helping smother the effects of the car's considerable weight, meaning that no matter what you're up to, the car feels reasonably light on its feet. It never feels small, though, commanding the respect of the driver and plenty of space from other road users.

And boy, do you need some space if you kick the S63 into Sport mode. In true AMG style, the electronic reins relax and the big luxury coupe cheerfully kicks off. The tail will wriggle under an unsympathetic right foot, that signature V8 roar, crackle and hiss filling your ears. The S63 is always the harder-feeling car, but it delivers with a more sporting drive than the S560.

Being the generous soul I am, I volunteered to return the S63 to its home for the evening rather than consign it to the back of a truck. On the back roads I took to reach the highway, it was rock solid - fast, predictable and a lot of fun. Once I found the boring straight bits, it turned into a supremely comfortable cruiser, ticking along in ninth at the legal limit (and being Melbourne, it was very much the legal limit), dispatching overtaking with barely a flex of a toe. 

The active cruise took the stress of keeping away from the State Revenue Office's clutches while being quiet and utterly pleasant.

The S-Class coupe comes loaded with eight airbags, ABS, stability and traction controls, forward and reverse AEB with pedestrian detection, reversing camera, crosswind assist (I know, right?), traffic-sign recognition and reverse cross traffic alert.

The S-Class Coupe does not have an ANCAP or EuroNCAP rating.

The GAC M8 is backed by a seven-year, unlimited-kilometre warranty, along with five years' complimentary roadside assistance, which is competitive against several of its nearest rivals. Service pricing has yet to be confirmed, though servicing is scheduled at 12-month or 15,000km intervals.

For now, the service network is limited, with around 10 centres nationwide, though GAC offers authorised servicing through third-party providers such as MyCar, which helps broaden access in the short term.

Mercedes offers a three-year/unlimited-kilometre warranty with roadside assist for the duration.

The company also offers both service plans (where you pay up-front as part of the vehicle purchase) and capped-price servicing on the coupes. Servicing over three years is in the order $2500.