Audi RS6 vs Mercedes-AMG GLE63

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.

There’s little wonder the GLE63 S is back for a second go around, after  clearly putting the frighteners on the Audi RS Q8 and BMW’s X5 M Competition and X6 M Competition.

After all, it’s a large SUV that sacrifices little in the way of practicality (especially the wagon) in its pursuit of high performance.

And for that reason, we’re itching to go for another drive – with or without the family.

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

“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.

First things first, the new GLE63 S is available in two body-styles, with the wagon appealing to the traditionalists out there, while the coupe targets the style-conscious.

Either way, few large SUVs are as imposing as the GLE63 S, which is a good thing considering it wants to be taken seriously.

Up front, it’s immediately identifiable as a Mercedes-AMG model thanks to its distinctive Panamericana grille insert.

The angry look is punctuated by the angular daytime running lights integrated into the Multibeam LED headlights, while the chunky front bumper has large air intakes.

Around the side, the GLE63 S stands out with its aggressive wheelarch extensions and side skirts, with the wagon getting 21-inch alloy wheels as standard, while the coupe gets 22-inch items.

From the A-pillars onwards, the differences between the wagon and coupe body-styles start to become apparent, with the latter’s roofline much more steeply raked.

At the rear, the wagon and coupe differentiate themselves even more clearly with their unique tailgates, LED tail-lights and diffusers. That said, they do have a sports exhaust system with squared-off quad tailpipes in common.

It’s worth mentioning that the difference in body-style also means a difference in dimensions, with the coupe 7mm longer (4961mm) than the wagon, despite having a 60mm-shorter wheelbase (2935mm). It’s also 1mm narrower (2014mm) and 66mm shorter (1716mm).

Inside, the GLE63 S separates itself with its flat-bottom steering wheel with Dinamica microfibre accents, and multi-contour front seats, which are upholstered in Nappa leather alongside the armrests, dashboard and door shoulders and inserts.

The door bins are of the hard plastic variety. That’s underwhelming in a vehicle that costs this much, as you would hope cow hide – or at least a soft-touch material – would be applied to them.

The black headliner acts as another reminder of its performance focus, and while it makes for a darker cabin, metallic accents feature throughout, while the trim (our test vehicle had open-pore wood) adds some variety alongside the ambient lighting.

That said, the GLE63 S is still filled to the brim with cutting-edge technology, including two 12.3-inch displays, with one the central touchscreen and the other a digital instrument cluster.

Both use Mercedes’ MBUX multimedia system and feature Apple CarPlay and Android Auto support. This set-up is still the benchmark, thanks to its speed and breadth of functionality and input methods, including always-on voice control and a touchpad.

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.

Being a large SUV, you’d expect the GLE63 S to be quite practical, and it is, but what you wouldn’t expect is the coupe to have 25L more cargo capacity than the wagon, at a generous 655L, due to its higher window line.

That said, when you stow the 40/20/40 split-fold rear bench via the second row’s release latches, the wagon has a significant 220L advantage over the coupe, at a cavernous 2010L, thanks to its boxier design.

Either way, there’s a small load lip to contend with, making loading bulkier items a little more difficult, although that task can be made easier with the flick of a switch, as the air springs are able to lower the load height by a handy 50mm.

Better yet, four tie-down points are on hand to help secure loose items,  alongside a couple of bag hooks, while a space-saver spare resides under the flat floor.

In the second row, things are even better, with the wagon offering a crazy amount of legroom behind our 184cm driving position, as well as two inches of headroom for me.

With its 60mm-shorter wheelbase, the coupe naturally sacrifices some legroom, but it still provides three inches of legroom, while its sloping roofline trims headroom to an inch.

No matter the body-style, the five-seat GLE63 S is wide enough to seat three adults abreast with few complaints, with the transmission tunnel on the smaller side, meaning there’s plenty of room for feet.

There’s also plenty of room for child seats, with two ISOFIX and three top-tether anchorage points on hand for fitting them.

Amenities-wise, rear occupants are treated to map pockets on the front-seat backrests, as well as a fold-down armrest with two cupholders, while the door bins can accommodate a couple of regular bottles each.

A  fold-out cubby is positioned below the air vents at the rear of the centre console, containing two slots for smartphones as well as a pair of USB-C ports.

In the first row, occupants have access to the centre console’s cubby, which features two temperature-controlled cupholders, in front of which are a wireless smartphone charger, two USB-C ports and a 12V power outlet.

The central storage bin is pleasingly large and contains another USB-C port, while the glovebox is also on the larger side, and you get an overhead sunglasses holder too. Stunningly, the front door bins can take three regular bottles apiece. Not bad.

While the wagon has a large, square rear window, the coupe’s is a letterbox in comparison, so rearward visibility isn’t one of its strong suits.

Priced from $220,600 plus on-road costs, the new GLE63 S wagon is $24,571 dearer than its predecessor. While the rise is unfortunate, it is accompanied by the fitment of a lot more standard equipment.

And the same is true of the new GLE63 S coupe, which is priced from $225,500, making it $22,030 more expensive than its forebear.

Standard equipment for both cars includes metallic paintwork, dusk-sensing lights, rain-sensing wipers, power-folding side mirrors with heating, side steps, soft-close doors, roof rails (wagon only), keyless entry, rear privacy glass and a power-operated tailgate.

Inside you score push-button start, a panoramic sunroof, satellite navigation with live traffic, digital radio, a 590W Burmester surround-sound system with 13 speakers, a head-up display, a power-adjustable steering column, power-adjustable front seats with heating, cooling and massaging functionality, heated front armrests and outboard rear seats, four-zone climate control, stainless-steel pedals and an auto-dimming rearview-mirror feature.

Rivals for the GLE63 S include the less expensive Audi RS Q8 ($208,500) and BMW’s X5 M Competition ($212,900) and X6 M Competition ($218,900).

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.

The GLE63 S is powered by Mercedes-AMG’s ubiquitous 4.0-litre twin-turbo V8 petrol engine, with this version pumping out a hard-hitting 450kW of power at 5750rpm and 850Nm of torque from 2250-5000rpm.

But that’s not all, because the GLE63 S also has a 48V mild-hybrid system called EQ Boost.

As its name suggests, it has an integrated starter-generator (ISG) that can provide up to 16kW and 250Nm of electric boost in short bursts, which means it can also reduce the sensation of turbo lag.

Mated to a nine-speed torque-converter automatic transmission with paddle-shifters, and Mercedes-AMG’s fully variable 4Matic+ all-wheel-drive system, the GLE63 S sprints from a standstill to 100km/h in just 3.8 seconds, in either body-style.

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.

The GLE63 S’s fuel consumption on the combined-cycle test (ADR 81/02) varies, with the wagon achieving 12.4L/100km, while the coupe needs 0.2L more. Carbon dioxide (CO2) emissions are 282g/km and 286g/km respectively.

When you consider the high level of performance on offer, all of these claims are fairly reasonable. And they’re made possible by the engine’s cylinder-deactivation technology and the 48V EQ Boost mild-hybrid system, which has coasting and extended idle-stop functionality.

That said, in our real-world testing with the wagon, we averaged 12.7L/100km over 149km. While that’s a surprisingly good result, its launch drive route mainly consisted of high-speed roads, so expect a much higher number in metropolitan areas.

And in the coupe, we averaged a higher but still respectable 14.4L/100km over 68km, although its launch  route purely involved high-speed country roads, and you know what that means.

For reference, the wagon has an 80L fuel tank, while the coupe has an 85L unit. Either way, the GLE63 S only takes more expensive 98RON premium petrol.

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.

Make no mistake, the GLE63 S is a big beast, but it certainly doesn’t act its size.

Firstly, the GLE63 S’s engine is an absolute monster, helping it to hunker down off the line and then charge on towards the horizon with serious vigour.

While there’s so much initial torque to begin with, you still get the added benefit of the ISG, which helps to eliminate lag as the new twin-scroll turbos spool up.

That said, acceleration isn’t always brutal, as the electronic stability control (ESC) is often quick to cut power when under full throttle in  first gear. Thankfully, engaging the ESC system’s Sport mode solves this issue.

This behaviour is somewhat ironic as the 4Matic+ system is seemingly never short of grip, with it's working hard to find the axle with the most traction, while torque vectoring and a rear limited-slip differential proportion torque from wheel to wheel.

Regardless, the transmission provides predictably smooth and predominantly timely gear changes, although they’re definitely not dual-clutch quick.

What’s more memorable, though, is the sports exhaust system, which keeps your neighbours relatively sane in the Comfort and Sport drive modes, but will drive them mad in Sport+, with hilarious crackles and pops heard loud and clear on the overrun.

It’s worth noting that while the sports exhaust system can be manually engaged in the Comfort and Sport drive modes via a switch on the centre console, it only makes the V8 rumble grow stronger, with the full effect only unlocked in Sport+.

Of course, there’s more to the GLE63 S experience, like the fact that  it somehow rides like a large SUV yet handles like a sports car.

The suspension’s air springs and adaptive dampers offer up a luxurious ride in the Comfort drive mode, with the GLE63 S wafting along with confidence. Not even its large-diameter alloy wheels pose too much of a threat to this quality on poorer country roads.

The ride is still more than liveable in the Sport drive mode, although the adaptive dampers become a  too firm in Sport+, with the ride becoming a little too jittery to be bearable.

Of course, the whole point of the adaptive dampers becoming progressively firmer is to help the GLE63 S handle even better, but the real revelations here are the active anti-roll bars and engine mounts, which effectively limit body roll to such a level that it’s almost imperceptible.

In fact, overall body control is impressive, with the GLE63 S not feeling like the 2.5-tonne-plus behemoth it is. It really has no right to attack corners the way it does, with the coupe feeling a touch tighter than the wagon, thanks to its 60mm-shorter wheelbase.

Further confidence is afforded by the sports brakes, which include 400mm discs with six-piston calipers up front. Yep, they wash away speed with ease, which is exactly what you’d hope for.

Also key to the handling is the electric power steering, which is speed-sensitive and has a variable ratio. It’s really quick in the wagon, and even more so in the coupe, thanks to its more direct tune.

Either way, this set-up is well-weighted in the Comfort drive mode, with plenty of feel and just the right amount of heft. That said, Sport and Sport+ make it gradually heavier, but neither make the driving experience better, so stick with the default setting.

Meanwhile, Noise, Vibration and Harshness (NVH) levels are pretty good, although tyre roar is consistent at highway speeds, while wind whistle is prominent over the side mirrors when travelling above 110km/h.

ANCAP awarded the second-generation GLE range its maximum five-star rating in 2019, meaning the new GLE63 S gets full marks from the independent safety authority.

Advanced driver-assist systems generously extend to autonomous emergency braking with pedestrian and cyclist detection, lane-keep and steering assist (including emergency), adaptive cruise control with stop and go functionality, traffic-sign recognition, driver attention alert, high-beam assist, active blind-spot monitoring and cross-traffic alert, tyre pressure monitoring, hill-descent control, park assist, surround-view cameras and front and rear parking sensors.

Other standard safety equipment includes nine airbags, anti-skid brakes, electronic brake-force distribution and the usual electronic traction and stability control systems.

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.

As with all Mercedes-AMG models, the GLE63 S comes with a five-year/unlimited-kilometre warranty, which currently sets the standard for the premium market. It also comes with five years of roadside assistance.

Better yet, the GLE63 S’s service intervals are relatively long, at every year or 20,000km – whichever comes first.

It’s also available with a five-year/100,000km capped-price-servicing plan, but it costs $4450 in total, or an average of $890 per visit. Yep, the GLE63 S isn’t exactly cheap to maintain, but you expected that.