Audi RS6 vs Mercedes-AMG GLC63

What's the difference?

You’ll notice a number out of 10 on this review, you should ignore it.

Not only is it irrelevant because you can’t buy one, but the RS6 Avant GT isn’t a ‘brain’ car, it’s a ‘heart’ car. As much as a five-seat wagon can be, anyway.

Whether you think it’s overkill, overpriced, or overhyped, the GT is a celebration of a car that’s become such an icon for petrolheads. It’s also probably a marker for the end of an era, because we don’t see many V8 family cars getting about anymore.

Well done to Audi, the accounting team in particular, and if anyone who owns an Avant GT is willing to let me have another drive, my in-box is open. 

Or I’ll just keep an eye out.

Obviously, I had nothing to worry about. The GLC 63 S is the same boisterous, silly car I drove 18 months ago, just with a few new bits to improve the package. As ever, the GLC 63 S is all about the experience - big noise, huge grip but all in comfort with plenty of gadgets.

The only real issues are price, service pricing and the length of the warranty. The first two probably won't bother most owners and one hopes the third won't be problem, but it would be nice if the length was reflected in the price.

If you care about badge, it has impeccable credentials, the AMG stripes and that plate on the engine with the builder's name. They're good credentials. The GLC 63 S has some very determined and capable competition, but none of them blend the speed, overall comfort and sheer sensory silliness of the AMG.

“It looks like a toy car you’d get in a Kinder Surprise” was the first comment from my housemate upon seeing the $400K collector's item on wheels.

Harsh, but to anyone unfamiliar with the Audi 90 quattro IMSA GTO racer, there’s arguably too much going on with the RS6 Avant GT.

The red, grey and black decals, the chunky white 22-inch wheels, the flared and vented front fenders and the wing over the rear window… all of it is a lot to take in, but it’s very faithful to the IMSA car.

As pictured, the 90 quattro IMSA has the red around the bottom lip of the car, on the bonnet, and even its rear wind, the same as the red on the rear of the Avant GT.

Some of the black at the front of the car, where the bonnet and fenders are, is just exposed carbon-fibre rather than a black decal.

Short of the sponsors and racing numbers, the Avant GT does a fabulous job of paying homage to the 1989 race car. It just means you’re going to be the centre of attention anywhere you drive. Or park.

On that note, an alternative paint and graphic scheme in 'Mythos Black' (this car is 'Arkona White') was available to customers and is decidedly more ‘under the radar’. You have to wonder, though, if you opted for the subtle version of a car that pays homage to a fire-breathing IMSA car, would you feel like you took the coward's option?

Besides, you’re either keeping this car in some kind of temperature-controlled bubble, or (hopefully) spending most of your time around it in the driver’s seat. From there, you don’t have to grapple with the question of garishness.

The interior is, while elevated past standard RS6 vibes, a lot more subtle. Dark materials of microfibre, carbon, leather and the smudge-prone piano black (an Audi favourite) are joined by a relatively restrained serving of red in the contrast stitching and seatbelts.

As before, the GLC 63 S comes in wagon and couple bodystyles. Little has changed, with just the usual tweaked front and rear bumpers and mildly redesigned headlights.

All the good bits have remained, like the 'Panamericana' grille from the AMG GT monsters, the jet wing-inspired front bumper and plenty of open space to feed the radiators and intercoolers.

Neither the wagon nor coupe is a pretty machine, but no mid-size SUV is much of an oil painting, with the exception of the Jaguar F-Pace.

The 'Night Package' is still a standard inclusion, blacking out various bits and pieces and looking good when allied with the dark alloys. They both look tough, though, which is classic AMG DNA.

Inside is pretty much the same as before, with just two obvious changes. The new Alcantara-trimmed steering wheel, again from the AMG GT, and also on the C 63 S, joins the party with a more expensive look and feel.

And the new MBUX screen is wider and looks much more at home in a $165,000-plus car. It's still a bit old-feeling, but the digital dash adds a bit of techno-style while the garish speaker covers don't.

You’ve bought a $400K collectible sports car capable of effortlessly deleting kilometres of highway with your family and enough luggage for a week. Usually a special edition driver's car at this price point is doing well if it has a place to put a phone and a water bottle, let alone phones and water bottles for four people - five if you really need.

Yes, in the performance car world, the Audi RS6 Avant has long been king of the convenience game and the GT holds onto that. 

The seating position and ergonomics remains comfortable, the driver’s seat being manually adjustable means it can sit even lower, there’s decent storage in the door cards, cupholders are able to be hidden, the phone charger is under the armrest, there’s a spot for small items like keys, change or glasses and the rear seats have mostly the same alongside their own individual climate controls and heated seats.

Behind those, a 548-litre boot puts most performance cars to shame, but its 1658L space when the rear seats are folded down is unbelievable for something that you’d want to take to a race circuit.

A family of four will love any GLC. The wagon's extra headroom over the coupe is useful if not life-changing, while the knee, leg and foot room are generous. Front seat passengers enjoy comfortable seating as long as you're not too keen on pudding.

Underneath, the upward sweep of the centre console is a pair of cupholders and a wireless charging Qi pad that will fit larger phones. Under the split armrest is a small but handy console bin, inside which you'll find USB-C ports.

Two more USB-C ports in the rear join a 12-volt socket and there are also climate controls for the rear seat passengers. The centre armrest pops open with a shallow, carpet-lined tray and two cupholders pop out the front. Each of the four doors has a bottle holder, too.

The boot space is unchanged for each bodystyle - 550/1600 litres for the wagon and 500/1400 litres for the coupe. Both have high loading lips, which is something to consider if you're hauling heavy things about or have trouble lifting items to a reasonable height.

As before, we get two bodystyles and the high(er) performance version, the GLC 63 S (a 'base' GLC 63 is available in other markets). Mercedes followed everyone else's lead and realised nobody would buy the skim milk version.

Unfortunately, that translates to the highest sticker price of the three, with the wagon coming in at $164,900, and the coupe at $171,900, before on-road costs.

That doesn't seem to hurt Mercedes too much with other cars in the range, but it's a significant difference. Incidentally, both prices are up by about $3000.

It's loaded, though - 21-inch wheels, multi-zone climate control, air suspension with dynamic dampers, electric and heated front seats, active cruise control, head-up display, reversing camera, around-view cameras, sat nav, front and rear parking sensors, keyless entry and start, electric tailgate, Nappa leather and wood trim, active LED headlights, auto wipers, auto parking, roof rails, sunroof, DVD player, and TV tuner, but no spare tyre, just a repair kit.

A Burmester-branded 13-speaker sound system is powered by Mercedes' spangly MBUX system on a new 10-inch touchscreen, which is much nicer than the old software and hardware combo.

MBUX offers deeper integration with the car's systems. The 'Themes' function is like a series of shortcuts to set the car up for a particular mood, but let's face it, most GLC 63 S drivers are just going to find the 'Race' function and go for it.

MBUX also has Apple CarPlay and Android Auto, but via USB only.

Audi’s venerable 4.0-litre, twin-turbo V8 engine remains at the heart of the RS6, though in the GT there’s no more power than the RS6 Avant Performance.

That means 463kW of power and 850Nm of torque delivered to all four wheels via an eight-speed torque converter automatic and Audi’s ‘quattro’ all-wheel drive system, making the RS6 Avant GT capable of a 3.3-second sprint to 100km/h, according to Audi. Top speed is a blistering 305km/h.

All this in a car I took to Coles.

An AMG 4.0-litre twin-turbo V8 brings the thunder, with a massive 375kW and 700Nm of torque. That's plugged into a nine-speed MCT (multi-clutch as opposed to twin-clutch) transmission and Merc's '4Matic+' all-wheel drive system.

With all that power and grip, you'll crack the ton in a supercar-baiting 3.8 seconds. One little point to note is the engine has active mounts.

Should you fancy turning your tinny into a landspeedboat, you can tow up to 2000kg for a braked trailer, and 750kg unbraked.

Do you care about this section of the review if you’ve bought one? Surely not. 

Anyway, Audi claims 11.8L/100km in terms of fuel consumption and you’d better believe it’s 98 RON minimum. 

It’s got a 72-litre fuel tank, which was depleted rather rapidly on test. While driving conditions weren’t ‘fair’ in terms of the test given the content demands of a short-term loan, there’s probably a realistic figure somewhere between the claim and the 17.9L/100km I achieved over a few days.

Mercedes reckons you'll get 12.2L/100km on the combined cycle which seems laughable at first and then you see what it actually does. To be fair, the car I drove on the launch copped a hammering and was hovering around the 17.0L/100km, with the start-stop and coasting functions playing only cameo roles.

There’s something unfortunate about how good the Audi RS6 Avant GT is from behind the wheel. That’s knowing how few people will properly get to enjoy it.

Not just because only 660 were built, but also because the majority of those 660 owners will be too worried about how much they’ve just spent on an automotive rarity to properly take it for a burn on a road, or even a track.

The RS6 was always an icon of Germany's penchant for subtle-looking cars that just happen to be capable of embarrassing much more brash vehicles, but the GT does away with the pretence and sharpens its teeth a little.

The specifically tuned rear differential makes for a more rear-biased driving experience in Dynamic mode, which means more agile cornering and a more natural balance compared to the way the RS6 sometimes feels - like a family wagon.

Its rival, the BMW M5 Touring, can go full rear-drive, but the Audi doesn’t need that as an option. It feels more capable and composed; ready to obey commands without fuss. A set of Continental SportContact 7 tyres (285/30) help there on the grip front.

The suspension underneath, adjustable coil-overs with three settings, is unique to the GT and lowers the ride height by 10 millimeters. It’s stiffer, 30 per cent at the front and 80 at the rear, and you notice it.

There’s more control and much less body roll, but the trade-off is the RS6 Avant GT is a little less comfortable on Australia’s particularly rough roads. Its 22-inch wheels don’t help.

It’s not, however, crashy or rattly. The suspension still does a fine job of stopping the driver being jostled around, but there’s a decidedly firmer response to the surface underneath. Again, still very composed.

With the new suspension, steering the GT feels easier than memory would suggest and the baseline was already good. There’s no unnecessary weight, but there’s still decent feedback from the front wheels and accuracy is bang-on.

Throttle adjustment in the corners, too, is easier with the rear differential, and it means anyone who still had reservations about Audi and understeer can be proven wrong.

The drivetrain remains unchanged from the Performance, which is a good thing. The effortless acceleration, even in the more aggressive 'Dynamic' setting with the transmission set to 'Sport' is smooth but seemingly unending.

Fortunately, the 4.0-litre V8 under the carbon bonnet sounds delightfully burbly, so getting to the speed limit or overtaking is a little treat every time. While the steering wheel paddles are there if you really need to drive in anger, the eight-speed is fine left to its own devices.

A 2.0-tonne family wagon with a V8 up front, easy communicative steering, and sporty suspension that settles well over bumps but allows enthusiastic corner attacks?

The RS6 Avant GT is in limited company.

Like any V8-powered AMG, the twin-turbo engine absolutely dominates the GLC 63 S. Even at walking speeds you can feel the serious firepower on offer, just a flex of your ankle away.

The figures are colossal - 375kW (over 500 horsepower) and 700Nm pushing around two tonnes of mid-sized SUV. Its famed bark is bettered only by Jaguar's completely unhinged, and surely borderline illegal, 5.0-litre supercharged V8.

You need to know you've got plenty of tech underneath you to make this stick to the road. The 21-inch alloys are wrapped in 265/40s at the front and 295/30s at the back, Continental Cross Contacts if you're interested.

They should - and would - ruin the ride, but the standard fitment of air suspension means that in normal driving, the GLC 63 S is firm but comfortable. A BMW X3 M is much harder, especially at the rear, going without the complex and heavier air set-up.

The air suspension is probably the pivotal piece of chassis tech that makes this car so versatile. While it's got driving modes up the wazoo - including the new 'Slippery' mode - it's a perfectly agreeable daily driver.

Leave it in comfort, accept that it has a firm ride and you're in good shape for the school run or the commute. You just sail along on a light throttle because there is virtually no turbo lag.

Whack it in Race and you can attack your favourite empty, bendy road with all the grip you could ever need.

The steering is remarkably light and direct for such a chunker and the optional carbon ceramic brakes were never bothered by what I could throw at them.

The V8 roars and spits and crackles, the gearbox shifting seamlessly up and down through the ratios. It's blissfully silly.

In a way, it's a velvet fist in an iron glove - comfortable inside but happy to headbutt the horizon with little provocation.

I'd prefer it if the transmission was a bit more decisive on slow speed shifts and you'll have to prepare yourself for a lot of wearying road noise on long trips. The latter is the price you pay for a ton of grip.

All GLCs have nine airbags, ABS, stability and traction controls, traffic sign recognition, around-view cameras, reversing camera, rear cross traffic alert, blind spot monitor, forward AEB, forward collision warning and tyre pressure monitoring.

There are also three top-tether mounts and two ISOFIX points.

The GLC scored a maximum five ANCAP stars in January 2016.

Audi’s five-year/unlimited kilometre warranty is below industry par, though most premium brands are in the same boat.

Twelve years of bodywork warranty against corrosion is also included, as is a five-year run of free Audi roadside assistance.

Five-year service plans can be purchased, or customers can buy back-to-back two-year extensions for the warranty, servicing and roadside assistance.

Mercedes Benz offers a three year/unlimited kilometre warranty with roadside assist which is not really up to scratch for a premium brand. Yes, the cars are complex but they're also expensive, so the investment should come with a commensurate warranty.

Service intervals are generous at 12 months/20,000km (as opposed to the 25,000km of other GLCs) and the capped price servicing means you'll know what you're paying.

Mercedes offers you the choice of an up-front payment or pay-as-you-go. Upfront ranges from $4050 for three services, $6100 for four, and $6850 for five.

If you go with PAYG, three services is a hefty $5000. Basically, each service is at least a grand when averaged out over time and that's pricey.

Service inclusions differ between your chosen method, but only slightly. The pricing includes filters, oil and, unusually, spark plugs and brake fluid, but that's small comfort.