Audi RS6 vs Mercedes-Benz GLS

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.

The GLS63 is an intimidating beast from afar, but it rewards its occupants in almost every way. Yep, there really isn’t a box it doesn’t tick without serious compromise, such is its breadth of capability.

If there was ever a Swiss Army Knife of cars, the GLS63 is definitely a contender for the title, one that makes it very hard to wipe the smile off your face. Just make sure you can fit it in your garage first…

“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.

If the GLS63 was a Marvel superhero, it would undoubtedly be the Hulk. Simply put, it has road presence like few others. In fact, it’s frankly menacing.

Of course, the GLS is already pretty intimidating due to its sheer size and blocky design, but the GLS63’s full-fat AMG treatment takes it to another level.

Naturally, the GLS63 gets an aggressive body kit, with its purposeful bumpers, side skirts and rear spoiler serving as instant reminders of what you’re dealing with, but it’s AMG’s signature Panamericana grille insert that really hammers home the point.

Around the side, the GLS63’s 22-inch alloy wheels with staggered tyres (front: 275/50, rear: 315/45) make their presence known, positioned below the wheelarch extensions.

That said, some fun’s also had at the rear end, where the GLS63’s diffuser element integrates the foreboding sports exhaust system with quad tailpipes very neatly.

The focused Multibeam LED headlights also look the part, while the opposing LED tail-lights tie everything together outside quite nicely.

Inside, the GLS63 stands out from the GLS crowd with its sports steering wheel with Dinamica microfibre accents, and multi-contour front seats, which are covered in Nappa leather alongside the armrests, dashboard and door shoulders and inserts.

Of note, the doors bins are unfortunately of the hard plastic variety, which is very disappointing in a vehicle that costs this much. You would expect that cow hide would also been applied to them, but alas it isn’t.

The GLS63’s black headliner serves as an obligatory reminder of its sporting intent, and while it makes for a dark cabin, metallic accents are prominent throughout, while the optional trim (our test vehicle had carbon-fibre) mixes things up, alongside the ambient lighting.

And let’s not forget the GLS63 is still loaded with plenty of cutting-edge technology, including a pair of 12.3-inch displays, with one the central touchscreen and the other the digital instrument cluster.

Both are powered by Mercedes’ class-leading MBUX multimedia system and feature Apple CarPlay and Android Auto support. This set-up arguably remains the best there is today thanks to its speed and breadth of functionality and input methods.

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.

Measuring 5243mm, 2030mm wide and 1782mm tall with a 3135mm wheelbase, the GLS63 is an upper-large SUV in every sense of the term, which means it’s also very practical.

For example, cargo capacity below the load cover is decent, at 355L, but stow the 50/50 power-split-folding third row via the boot and it’s very good, at 890L, or drop the 40/20/40 power-split-folding middle bench, too, and it becomes a cavernous 2400L.

Better yet, the boot’s aperture is almost square, and its floor’s flat, while there’s no load lip to contend with, making loading bulkier items even easier. Up to four tie-down points are also on hand (depending on seating configuration) to secure loose cargo.

Under the false floor is the space-saver spare, which is to be expected, but what isn’t expected necessarily is the fact there’s also enough room there for the cargo cover when it’s not in use, which would be the case if six or more passengers are regularly onboard.

Moving into the power-sliding second row, the GLS63’s practicality is once again brought to the fore, with up to six-plus inches of legroom available behind my 184cm driving position.

There’s also two inches of headroom with the panoramic sunroof in situ, not to mention just enough toe-room. The GLS63’s small transmission tunnel and sheer width also mean three adults can be seated on the middle bench with few complaints.

Amenities-wise, the second row has map pockets on the front-seat backrest and a small fold-down cubby below the rear climate controls, with it containing two slots for smartphones and a pair of strategically placed USB-C ports.

The rear door bins can take one large bottle each, while a fold-down central armrest is also on hand, featuring a shallow tray and retractable (and flimsy) cupholders.

Alternatively, the $2800 Rear Seat Comfort Package fitted to our test vehicle subs in a tablet that can control the multimedia system, a wireless smartphone charger and a small cubby into the former, as well as a heated/cooled cupholder atop the rear of the centre console.

In the third row, it’s not quite as roomy if you’re an adult. With the middle bench in its most accommodating position, my knees still brush up against its backrest, which is to be expected given it’s primarily designed for children. I also have an inch of headroom there.

Nonetheless, getting in and out of the third row is relatively easy as the power-operated middle bench tumbles forward and provides just enough space to make entry and exit somewhat graceful.

When seated, rear occupants are treated to two USB-C ports and one small cupholder each, so they’re arguably taken better care of than those in the middle.

Child seats are well and truly accommodated, with four ISOFIX and five top-tether anchorage points fitted across the second and third rows, although the latter will inevitably prove to be a much tighter fit.

The driver and front passenger are still taken care of, with a front cubby taken up by two heated/cooled cupholders, a wireless smartphone charger, two USB-C ports and a 12V power outlet, while their door bins take one large and one small bottle each.

In-cabin storage options include the large central storage bin, which hides another USB-C port, while the glovebox is on the smaller side, with about a third of it taken up by the fragrance, which is pumped into the cabin to ensure the interior always smells its best.

Priced from $255,700 plus on-road costs, the GLS63 commands a $34,329 premium over its predecessor, although buyers are arguably getting more bang for their buck than before, even if it does sit well clear of the two other GLS variants: the $147,100 GLS450 and $153,900 GLS400d.

Standard equipment not already mentioned in the GLS63 includes regular metallic paintwork (our test vehicle was finished in Selenite Grey), dusk-sensing lights, rain-sensing wipers, power-folding side mirrors with heating, soft-close doors, roof rails, rear privacy glass and a power-operated tailgate.

Inside, keyless entry and start, augmented reality (AR) satellite navigation with live traffic, digital radio, a 590W Burmester surround-sound system with 13 speakers, a head-up display, a panoramic sunroof, heated seats (including middle outboard) and armrests, cooled front seats with massaging functionality, power-adjustable seats, a power-adjustable steering column, temperature-controlled front cupholders, five-zone climate control, stainless-steel pedals and an auto-dimming rearview mirror feature.

With BMW not offering an X7 M (although the slightly smaller $209,900 X5 M Competition is available) and the $208,500 Audi RS Q8 really from the segment below, the GLS63 does not have a direct rival in the Upper-large SUV segment.

In fact, the $334,700 Bentley Bentayga V8 is actually the model that comes closest to the GLS63 when looking for a seven-seater with a similar level of bent-eight performance.

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 GLS63 is powered by a familiar 4.0-litre twin-turbo V8 petrol engine, with its version producing a thumping 450kW of power at 5750rpm and 850Nm of torque from 2250-5000rpm.

This unit is mated to a nine-speed torque-converter automatic transmission and AMG’s fully variable 4Matic+ all-wheel-drive system with torque vectoring and a rear limited-slip differential.

This set-up also features Mercedes’ EQ Boost 48V mild-hybrid system, which actually gives a 16kW/250Nm electric boost in short bursts, such as when accelerating off the line.

Speaking of which, the GLS63 sprints from a standstill to 100km/h in just 4.2 seconds, while its top speed is electronically limited to 250km/h.
 

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 GLS63’s fuel consumption on the combined-cycle test (ADR 81/02) is 13.0L per 100km, while its carbon dioxide emissions are 296 grams per km. All things considered, both claims are unsurprisingly high.

In our real-world testing, we averaged a fearsome 18.5L/100km over 65km of driving, split between highways and country roads, so not your usual mix. A very heavy right foot definitely influenced that result, but don’t expect to do too much better in a normal run.

For reference, the GLS63’s 90L fuel tank can be filled up with 98RON petrol at a minimum.

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.

Frankly, the GLS63 has absolutely no right being as capable as it is. It’s a really big bus that’s legitimately convinced it’s a sports car half its size.

Being a GLS variant, the GLS63 has independent suspension consisting of four-link front and multi-link rear axles with air springs and adaptive dampers, but its party trick is the addition of active anti-roll bars.

In what feels like magic, the GLS63 is simply not intimidated by corners, despite having massive dimensions and a considerable 2555kg (kerb weight) to deal with.

The active anti-roll bars make the GLS63 so much easier to drive fast through the twisty stuff, almost eliminating body roll, taking one key variable out of the equation for the driver. Active engine mounts are also fitted, helping to settle things even further.

The electric power steering on hand is also good. It is speed-sensitive and has a variable ratio, which basically makes the set-up more direct when it needs to be. It’s typically light in hand, too, until one of the sportier drive modes is engaged and extra heft is added.

So, handling is scarcely believable, which means the ride must be compromised, right? Yes and no. With the adaptive dampers in their softest setting, the GLS63 is very compliant. In fact, we’d say it feels luxurious when compared to other high-performance SUVs.

That said, our test vehicle was fitted with the optional 23-inch alloy wheels ($3900), which look the part but expose sharp edges and other road imperfections, not to mention generate noise easily heard inside. Naturally, feedback is exacerbated in the sportier drive modes.

Anyway, there’s more performance, and the GLS63 has the rest in spades. Its engine is a powerhouse in every sense of the word. It’s so powerful, in fact, that it hilariously hunkers down off the line or when suddenly accelerating at low speed.

Thanks to the mild-hybrid system, wads of torque is available from the get-go, making for a highly responsive driving experience, even in those rare moments when the engine isn’t on song.

While not as characterful as some of the other members in the 63 series, the GLS63 still makes some thoroughly entertaining noises, with its sports exhaust system popping like mad while on the overrun.

All of this ability is very well and good, but you need to be able to pull up quickly, and the high-performance braking package (400mm front and 370mm rear discs with six-piston fixed callipers and single-pot floating stoppers respectively) mercifully does exactly that.

Neither ANCAP nor its European counterpart, Euro NCAP, have awarded the GLS range a safety rating, but it’s fair to assume it would perform well in testing.

Advanced driver-assist systems in the GLS63 extend to autonomous emergency braking with pedestrian and cyclist detection, lane-keep and steering assist (including emergency), adaptive cruise control, active blind-spot monitoring, rear cross-traffic alert, traffic sign recognition, driver attention alert, high-beam assist, tyre pressure monitoring, hill-descent control, hill-start assist, park assist, surround-view cameras and front and rear parking sensors.

Other standard safety equipment includes nine airbags (dual front, front-side, curtain and rear-side plus driver’s knee), anti-skid brakes (ABS), electronic brake-force distribution (EBD) and the usual electronic stability and traction control systems. Yep, it doesn’t leave much to be desired on the safety front.

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 GLS63 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.

The GLS63’s service intervals are relatively long, at every 12 months or 20,000km (whichever comes first). Better yet, it’s available with a five-year/100,000km capped-price servicing plan, but it costs $4450.