BMW XM vs Audi RS6

What's the difference?

It’s pretty obvious the XM is designed to impress people with big wallets and an appetite for a techy experience that’s also not without a few green credentials. The ability to motor around as a fully-electric vehicle for up to 80km or so is a big plus and the electric-ballroom interior vibe is hard to ignore, as well.

But from our perspective, the full-fat, twin-turbo V8, while offering startling performance, is perhaps a lost opportunity to follow some of BMW’s competitors into the engine-downsizing space. Then again, when you floor the throttle and 2700kg hurtles forward like a big dog on a short chain, you can see where BMW is coming from.

Perhaps the biggest letdown is the ride quality – or lack of it. While it’s understandable BMW wanted the most dynamic version of the XM it could manage, the end result plays against the vehicle’s otherwise long suit of hyper-luxury. Doubtless, BMW would argue that to soften the chassis would have been to introduce a chink into a no-compromise product. But, perhaps, sometimes a sensible compromise is the way forward.

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 nothing subtle about the way the XM looks. It probably pulls up just short of brutalist (or maybe not) but even those who find its slabs and angles attractive have to admit that it’s bold.

The now-trademark giant nostrils set the mood and the rest of the exterior suggests some kind of armoured transport for presidents rather than wheels for the school run. Doubtless, this will hardly be seen as a fault by those in the market for such a thing.

The real surprise here is that the XM does not share a bodyshell with any other production BMW. Sure, the V8 petrol engine and wheelbase are common to other BMW and M models, but the sheet metal is the XM’s and the XM’s alone. That in itself, is quite a statement of intent.

“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.

Given the vast exterior dimensions and a weighbridge ticket the wrong side of 2700kg, it may come as a surprise to learn that the XM is strictly a five-seater with not even an optional third row.

That said, the uber-SUV Lexus LX in flagship, Ultra Luxury, trim offers just four seats in deference to the VIP clientele it’s pitched at, but also comes complete with reclining rear seats and a passenger’s side footrest which the XM can’t match.

Staying in the rear seat, there’s lots of legroom and plenty of space under the front chairs for feet. A lot of that is down to the wheelbase the XM shares with the BMW X7, and even behind a tall driver, there’s lots of space. In fact, compared with a BMW X5, there’s a full 150mm of extra legroom.

The pew itself flows into the door trims for a lounge effect which looks great with the contrasting light-coloured trim, and the centre arm-rest folds down to reveal a pair of cupholders. Extra storage space can be found in fold-out pockets in the rear of each front seat which also house a small, lidded panel that opens to reveal USB ports and power sockets. Dual-zone climate controls are also part of the rear-seat experience.

The gee-whizz stuff hasn’t been ignored, either, and the prismatic roof lining is nothing if not a talking point. But would a panoramic sunroof have been of more value to many buyers? The ambient lighting is a nice touch, too.

Up front, the view is dominated by the giant, twin curved animated dashboards. They deliver information and lots of it, to the point where it can almost seem a bit overwhelming.

The head-up display helps simplify things, but there’s absolutely no doubt there’s a lot going on in this cabin. Again, this is modern luxury motoring, but it remains that the menu system will take time to learn, even if the touchscreen function gives you an option on how you control things.

Multi-adjustable front seats are part of the deal and there’s an M-spec steering wheel which is heated. And although it features plenty of buttons, isn’t as daunting perhaps as the multi-spoked equivalent in some high-end AMGs of late.

The stereo system is also worthy of a mention, being a Bowers & Wilkins unit with roof mounted speakers and no less than 1500 watts of power. Digital radio is part of the package.

Even though it doesn’t offer a seven-seat option, luggage space in the rear of the XM is hardly class-leading. Cargo volume with rear seat up is 527L and 1820L with it folded.

Much of the wheelbase is devoted to rear-seat stretching room and although the batteries for the electric motor are positioned under the rear seat, the floor of the cargo area seems quite high.

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.

I’ve been told I’m not allowed to swear in CarsGuide reviews, so add your own expletive when I say, at $399,000, before on-road costs, the RS6 GT is expensive.

A ‘standard’ Audi RS6 Avant Performance costs $252,600, so you would really, really hope that warm feeling you get from owning one of only 22 GTs in the country is worth around $146,400. It’s very hard to imagine the physical changes to the car amount to that much money.

Of course, there’s plenty of kit in the RS6, anyway. But unique to the Avant GT is a carbon bonnet, carbon wing mirrors and carbon front fenders, a restyled spoiler, tailgate, and rear diffuser, 22-inch Audi Sport six-arm ‘Avus’-inspired alloy wheels (in white or black), RS ceramic brakes and black badging.

Inside, there are RS front bucket seats trimmed in leather, synthetic suede and carbon, contrast stitching in red, red seatbelts, black synthetic leather along the dashboard with open-pore carbon, rear window sunshades and a Bang & Olufsen 3D sound system from the 'Sensory Package' as standard.

There’s also ‘RS6 GT’ scuff plates, floor mats, puddle lighting and the individual number for each of the 660 cars on the centre console. 

There’s also manually adjustable coil-over suspension and a GT-specifically-tuned quattro sport differential.

It’s cool, but is it an extra $146K cool?

For the price, you’re almost in Ferrari territory, or you’re ticking some options boxes on your Porsche 911 Carrera T. Suppose neither of those can comfortably take a family of four on a holiday to the snow and even feel safe driving on icy roads, though.

It does happen to be about the same price as the Mercedes-AMG GT63 S 4 Door, though whether that looks as good as the RS6 is debatable.

Here’s where the XM starts to justify its price-tag. While the use of an electric motor to boost a petrol engine has allowed some manufacturers to reduce the capacity of the latter, no such restraint has been shown for the XM. Instead, it gets the full 4.4-litre, twice turbocharged V8 that we’ve come to know and love from this brand.

It’s not that this is the engine’s first date with hybrid technology, but the mild hybrids that have come before it can’t match the XM for sheer brutality when both power units are unleashed.

The petrol V8 can muster up 360kW and 650Nm which, when boosted by the electric motor, jumps to a total of 480kW (combined) and 800Nm.

While the petrol engine drives through an eight-speed torque-converter automatic, the electric motor also drives through the transmission, an arrangement that is a bit different to some hybrids which use the petrol engine for the rear axle and the electric motor to drive the front wheels.

Of course, the requirement for the XM to feature permanent all-wheel drive, regardless of what power unit is running at the time, forces this layout.

Speaking of all-wheel drive, The XM’s version of BMW’s 'xDrive' layout has been specifically tuned for this vehicle and includes torque vectoring as well as a limited-slip rear differential.

The system has the ability to vary the torque split front to rear, with the default rear-bias giving a more sporting feel on good surfaces. An active rear differential also helps give the car a rear-drive feel.

As well as modes for 'Hybrid', 'Electric' and 'eControl' modes, the XM sticks with the M tradition of offering two M buttons which can be configured to set the parameters for steering, driveline, chassis and, in the case of the hybrid XM, the degree of braking regeneration offered.

Four-wheel steering is also part of the XM’s repertoire and, interestingly, there’s no air suspension here; just conventional steel springs.

But it does feature an electrically-adjusted anti-roll bar system which aims to strike a happy medium between what the driver wants and the road conditions demand.

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.

A 25.7kWh lithium-ion battery provides the power for the electric drive. It’s mounted under the rear seat and can produce a purely electric range of between 82 and 88km (based on WLPT test protocols).

Charge time from a conventional wall-box is said to be about four hours but, interestingly, the XM has no provision for DC fast-charging.

Fuel consumption (combined cycle) is an EV-typical 2.7 litres per 100km, which equates to a low 61g/km of CO2.

Once you’ve depleted the battery on a highway journey, expect the petrol V8 to consumer somewhere between eight and nine litres per 100km at cruising speed.

Using EV mode means zero-emission operation but, as with any electric car, how the power is generated to recharge it determines its real-world green-ness.

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.

While any M car is supposed to be rapid and dynamic, it’s also true that the over-arching perception of big SUVs is that they’re comfortable and plush. None of which explains the ride in the XM.

Regardless of how you fiddle with the settings, the ride is always brittle. Those big tyres with their minimal sidewall somehow manage to find every crack and join in the road, and it’s these sharp-edged imperfections that thump through to the cabin the most vocally.

It’s enough to make you wonder who this car is going to appeal to. Will it take to race tracks? Almost certainly not. So the whole point of these suspension settings might be a bit lost on some people.

Performance, meanwhile, is insanely rapid for something that could pass as a bulk carrier. The biggest giveaway to the mass is the transmission’s earnest attempts to keep everything moving by feeling a bit hyperactive on downshifts.

Using the ratios is always going to be the strategy, but with all that torque, maybe it’d be nice sometimes for the trans to hang on to a taller gear and let the boost blow it towards the next corner.

The sound track? Polarising. Even if it doesn’t convince you that Hans Zimmer (who developed the various electronically-synthesised noises the XM makes) should stick to winning Oscars, the augmented sounds are background noise rather than the main event here.

Even the petrol V8’s naturally stirring backing vocals have been electronically tweaked with debatable results.

That said, it’s nice to have something to listen to that isn’t the insistent tyre roar which becomes even louder on coarse-chip surfaces.

Steering effort is light but there’s not a lot of feedback in terms of actual feel. In fact, it’s borderline detached and only the sheer speed of the rack confers any athleticism.

Also, the rear steering seems to come in a few milli-seconds after the front has started to turn. And for all that all-wheel-steering agility, this is never a car that shrinks around you.

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.

There’s no current rating from ANCAP for the A6 in general, let alone this specific RS6, but there’s a decent suite of safety equipment and tech to keep you worry-free in the GT.

Eight airbags and more than 30 driver assistance systems from the RS6 are of course present in the GT, including adaptive cruise control, lane-keep and warning, emergency brake assist and cross-traffic alert.

Audi’s also got surround view cameras for parking, which also includes warnings for approaching vehicles or objects, plus there are preemptive measures the car can take in an impact like tightening the seatbelts or braking to avoid a second collision.

The second row also has three top tethers and ISOFIX anchor points on the outboard seats for mounting child seats. 

Like a lot of manufacturers, BMW knows consumers can be leery of EV tech when it comes to the cost of battery replacement. So, as well as the five-year/unlimited-kilometre warranty on the whole vehicle, there’s also eight years or 160,000km of cover for the high-voltage battery.

Servicing intervals are based on how the car has been used and it will inform the owner when a service is required.

A servicing package is included in the purchase price and BMW even throws in three years of roadside assistance.

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.