Audi RS6 vs Mercedes-AMG GLC63

What's the difference?

To me at least, the RS6 is pretty much the ultimate fast and practical car. One which is just as comfortable plodding around town as it is tearing it up on the track. Keep in mind, too, this may be one of your last chances to have a car which looks like this, equipped with a V8 engine. So, have I convinced you? Would you consider one of these over a performance SUV? Tell us what you think in the comments below.

Note: CarsGuide attended this event as a guest of the manufacturer, with travel, accommodation and meals provided.

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.

At a distance the RS6 is just an unassuming station wagon, but the closer you get, the more apparent it becomes how mean it is. It’s wide, it’s chiselled, it’s not just good looking, it’s iconically Audi.

The stance is so wide, its ride height so low, and its wheels are so massive that any keen eye will be able to spot where the difference is between this and any old family hauler.

Wagons may not be trendy, but there’s something undeniably cool about having the hauling capacity of an SUV at the ride height of a sedan.

Of course, if you want to look even more svelte and don’t need the boot space, the RS7 is always lurking around at a slight price premium.

Inside, the RS6 has all the modern amenities of the Audi range. Expect the usual sharp screens, lovely sports seats, and a tasteful application of textures throughout.

There’s a blend of carbon-look finishes, chrome, leather and gloss black. Perhaps a little too much gloss black to keep clean, but the aesthetic is suitably upmarket. 

You can go to town on customisation, and the car we primarily tested had stitching and colour in the carbon patterns to match its 'Ascari Blue' exterior, but you can pick whatever shade or combination of colours your budget allows.

Audi’s software is pretty good these days, with an attractive theme and fast hardware to back it, and the brand’s ‘Virtual Cockpit’ is still one of the most aesthetically pleasing and customisable digital instrument systems on the market, despite being one of the first.

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.

Okay, I promised a car with the practicality of an equivalent SUV, but it’s not quite there. The trade-off is still worth it, I promise, but there are a few areas where the RS6 isn’t as practical as you think it’s going to be, particularly for front occupants.

Yes, it’s a big wide car, with large but supportive seats and plenty of headroom, but the issue for those travelling in the front two seats is the surprisingly limited amount of storage.

Yes, there are two bottle holders in the centre console with a folding tray lid to hide them away, but they aren’t huge. Bigger bottles would have to go in the door bins, but even then they’re a bit height-constrained.

There’s a decent glove box on the passenger side, but even the centre console box is very shallow, with more than half of it taken up by a wireless phone charger.

The touch panel for the climate unit looks impressive but still can’t match having physical dials. It has clicky haptic feedback to your individual presses, and all the functions are permanently accessible instead of hidden in sub-menus, so if you’re going to make climate a touch-based interface, it doesn’t get much better than this.

Where the RS6 shines is in the back seat. Despite those big bucket front seats, I had heaps of room behind my own seating position (at 182cm tall), with lots of headroom and sufficient width in the cabin to spread out.

You sink into the rear seats, which are heavily contoured so riding in the back is a pretty good experience even on the track.

Rear passengers get four adjustable air vents in both the B pillars and in the centre, as well as their own touch panel for the rear climate zone.

USB power outlets are also available, and there are netted pockets on the front of both back seats, with a further two bottle holders in the drop-down armrest.

The centre seat is probably only good for kids, because there’s a very tall raise in the centre required for the driveshaft, eating all the legroom.

The boot is fairly large at 548 litres which is in mid-size SUV territory, although I will admit some performance SUV rivals offer closer to 600L.

Space expands to 1658L with the second row folded flat.

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.

The RS6 is still packing eight cylinders in 2023, producing a massive 463kW/850Nm, somehow an increase (+22kW/50Nm) over the previous iteration.

Audi’s signature ‘Quattro’ all-wheel drive system is present alongside a limited-slip differential and four-wheel steering.

Air suspension and performance brakes and exhaust also feature, alongside an aggressive Continental SportContact 7 tyre package.

The 0-100km/h sprint time is now just 3.4 seconds, allowing you to show up even some electric cars, and the RS6 features 48-volt mild hybrid technology with a cylinder-on-demand system which can shut half the block down for more efficient coasting.

The transmission is an eight-speed torque converter unit which is smooth and effortless.

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.

Officially, the RS6 and its eight cylinders drink a combined 11.8L/100km, although even with its fancy hybrid system and cylinder deactivation, my time with the car saw 15.0L/100km. The RS6 has a 72-litre fuel tank and takes only the finest 98RON unleaded fuel.

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.

As you might have guessed from its impressive engine and performance equipment, the RS6 is a certified weapon on road and track.

On the road you can expect a quiet, refined cabin, superbly balanced steering for low and high speeds and a gentle ride quality courtesy of the pricey air set-up.

It’s as noisy or as quiet as you want it to be, with the cylinder deactivation toning things down at low speeds, and the engine roaring to life under heavy acceleration, or when the 'Dynamic' drive mode is selected.

It can at times be alarming how much the RS6 leaps to life, as it feels so cushy in a city, its width and cabin giving the feel of a luxury car rather than a performance one.

Make no mistake, though, the RS6 is properly quick, and when you give it a kick, it’s the roaring, aggressive machine the spec sheet suggests.

The best place for this? The track, of course. The big V8 and the capability of the all-wheel drive system are truly best explored at velocities impossible to legally achieve on the road.

Once you get past the bark and snarl of this wagon’s eight-cylinders at full force, and the lightning-fast shifts of its eight-speed automatic, you’ll have a moment to appreciate the way it simply holds to the tarmac when you tilt it into the corners, providing a balance when loaded up which only air suspension can provide.

The steering is awesome, communicating the texture of the road nicely to the driver, and requiring just the right amount of force to keep the car pointing where it needs to go.

The grip level is astounding with the huge tyres and the four-wheel steer system lets this hefty wagon take corners at a tighter angle than your brain initially allows.

Thankfully, the four-wheel steer system isn’t weird, either. While it can have a strange effect on some cars, in the RS6 it only bends your mind slightly when you tip it into a hairpin. Otherwise it feels pretty normal.

When everything is warmed up, it can let its guard down slightly and allows the driver to eke out a slide at the rear here and there for extra fun-factor

Jeez. What a machine. I guess this is what a quarter of a million dollars buys. A car that can do it all. Take the kids to the school in comfort and tear it up on the track like few other passenger cars on the same day.

There’s a caveat, though. A small one which looks like it will turn into a big one for cars like this in the near future.

I had the opportunity to drive the RS e-tron GT around the same circuit and it was better. Much better.

It was faster, more accurate, more composed. It was so effortless, I didn’t realise exactly how much quicker than the RS6 it was until I drove them back-to-back.

It’s a good sign for the future, but also a reminder a V8 like this isn’t the performance pinnacle it once was.

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.

Five years and unlimited kilometres is the warranty length, and Audi’s ownership program includes invites to events like the one we were able to experience for the launch of this car. A track-test of the RS6 and the RS e-tron GT.

If you own one, I recommend them, you’ll learn a thing or two about the car and possibly yourself while you’re at it.

Servicing is required once every 12 months or 15,000km, and a service pack covering the first five years or 75,000km can be purchased alongside the car at a cost of $4360.

It works out at $872 per year, which isn't economy car cheap, but with such a complex drivetrain, what did you expect?

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.