Mercedes-Benz G-Class vs BMW XM

What's the difference?

As per the 1979 original, the current G-Class is produced by Magna Steyr in Arnie’s home town of Graz in Austria. And many fundamental things haven’t changed since then. But clearly this EV monster’s exotic electric powertrain is a huge departure.

It retains impressive off-road ability and straight-line speed. But will it hit the mark with top-end luxury 4WDers? Short story, this thing is wild, and it will be irresistible for a likely narrow band of tech-focused ‘must have the latest and greatest’ buyers. Nothing like impressing friends and family with a tank turn.

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

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.

Okay, so Mercedes-Benz says, with a straight face, that “with the aim of optimising the vehicle’s aerodynamics” classic G-Class elements have been revised, including the reprofiled bonnet, ‘air curtain’ vents in the flares over the rear wheel arches, A-pillar cladding and the small spoiler on the edge of the roof.

At the same time, the 20-inch wheels are also claimed to be "aerodynamically optimised” and underneath, a 26mm underbody casing made from a mix of materials, including carbon-fibre (attached to the ladder frame with more than 50 steel screws), protects the battery from dust, dirt and rocks.

In ticking off the Edition One, car-spotters should look for black rims with blue brake callipers behind them, blue inserts in the exterior protective strips as well as black door handles and a new rectangular design box on the rear door for storing items such as charging cables, tools or snow chains. If you want a spare wheel, choose the standard model.

An optional black-panel radiator grille ($3800) features tinted lighting units as well as an animated LED light band and chrome surround. The light band can be activated as a running light or an animation when locking and unlocking the vehicle.

And it’s worth noting Mercedes-Benz and the car’s contracted manufacturer, Magna Steyr, have invested much time and many Euros in retaining the car’s classic handle and door lock design. G-Wagen owners will recognise its sound from several kilometres away.

Inside the G580 it’s clear this is one area where the G-Class has progressed enormously over the decades. It’s still quite upright in terms of the dash design, but you’re confronted by twin 12.3-inch screens, supporting the Mercedes-Benz user interface. 

All very high-tech, but that’s balanced by an old-school grab-handle for the front passenger to latch onto during off-road work. 

The signature turbine-style air vents are located within squared-off panels, and in the limited Edition One you have a blue fleck running through carbon-fibre inserts on the centre console, door cards and that front grab handle. In the standard car it’s a (very attractive) walnut open-pore wood rather than carbon.

A luxurious interior for sure.

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.

For the record, the G63 is just over 4.6m long and a little more than 1.9m wide with a 2890mm wheelbase. So, not huge, but its close to 2.0m height is hard to ignore. 

In the front there’s lots of breathing space, and in terms of storage you have generous bins in the doors with plenty of room for big bottles. Then there’s a centre armrest, which doubles as the top of a deep storage box housing a USB-C port inside. 

A sliding roller cover in the centre console reveals two cupholders, another two USB-C sockets, a 12-volt outlet and a wireless charging pad. Add in a big glove box and you’ve got plenty of options in terms of storage, power and connectivity. 

In the back, sitting behind the driver’s seat set for my 183cm position I’ve got tons of foot and legroom and, no surprise, lots of headroom.

There’s a fair bit of sculpting in the rear seat, which is as nice as it is unusual (makers often avoid bolsters on the rear seat as it makes the backrest harder to fold flat). And in terms of three-abreast accommodation, a smaller adult will be okay in the centre spot for shorter journeys. Three up to mid-teenage kids will be swimming in it.

Then, for practicality you again have generous bins in the doors. And if you need even more capacity, fold down the centre armrest which houses two different size cupholders. 

In the rear of the centre console you’ve got two USB-Cs, a 12-volt power outlet, individual climate control and directional vents.

There are map rockets on the front seatbacks and more air vents in the B-pillar. So, when it comes to comfort, powering up devices and storing ‘things’ you’re well taken care of.

The side-opening tailgate door opens from right to left, which isn’t ideal when parallel parked on the left hand side of the road, but boot volume is over 600 litres (VDA) with all seats upright, expanding to nearly 2000 litres with the 60/40 split-folding rear seat lowered.

There are multiple tie-down hooks, a netted pocket, two lights, a 12-volt outlet as well as a ‘ski-port’ door and sliding cargo cover to enhance practicality and security.

As mentioned earlier, the full-size spare in the standard model, but the Design Box replaces it on the Edition One, although Mercedes-Benz says it’s aiming to make a spare available as an option later in the year.

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.

The XM is one of those 'no options' vehicles. That is, you pay the basic price, you get one with the lot. The aged leather and even the optional 23-inch wheels and tyres are no-cost options, so it’s clear where BMW is aiming the thing.

As well as the plug-in driveline, all-wheel drive and all the M driving focus, the XM features plenty of tech including massaging front seats, heated seats all around, a high-end stereo, heated and cooled cupholders, four-zone climate-control, wireless phone charging and twin, curved info screens for the driver measuring 12.3 and 14.9 inches. The novel roof lining also features 100 pin-point LEDs for effect.

The cost of such detailing is a not insubstantial $302,200. That figure does, however, undercut two of its main rivals, the Lamborghini Urus ($395,888) and the Aston Martin DBX ($356,512).

It’s also worth mentioning that the XM is not even BMW Australia’s most expensive model; in fact, it’s fourth on the ladder.

The G580 is powered by four permanently excited synchronous motors, each delivering around a CLA200’s worth of power and torque to each wheel for overall outputs in excess of 432kW/1164Nm.

Each motor has its own two-stage transmission and power electronics for almost infinite fine-tuning of the direction and amount of drive sent to individual wheels. Merc calls it ‘individual-wheel drive’.

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.

Housed in a torsion-resistant casing and embedded low down in its ladder-frame chassis, the G580’s 116kWh two-tier, liquid-cooled lithium-ion battery pack delivers a WLTP-rated range of 473km, or 567km on the more lenient NEDC scale.

‘Eco Assistant’ and ‘Range Monitoring’ functions provide continuous information on battery status, energy consumption and estimated range.

Maximum system capacity is 400 volts which enables 200kW DC charging, meaning a 10 to 80 per cent fill in as little as 32 minutes. Maximum AC charging capacity is 11kW.

Claimed energy use is 23.1kWh/100km, and we saw an average of 28.6kWh across urban and highway running on the launch drive program.

Not exactly a ‘green’ EV choice, then, but it’s worth noting a one-year Chargefox subscription is included to off-set the car’s energy appetite.

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.

So, with 432kW and around 1160Nm, even though the G580 weighs in at around three tonnes, you’re talking 0-100 km/h in 4.7 seconds. And this car gets up and goes… like a beast.

What you don’t get is that traditional Merc-AMG G63 V8 rumble, because, of course, no engine. 

But you do get what Mercedes calls ‘G-Roar’, essentially a sound bar at the front of the car also using the audio system inside to give it what is not exactly an engine noise but some sense of the car progressing. And you can turn it off for completely silent running.

‘Electric Dynamic Select’ changes the parameters of the motors, transmission, suspension, ESP and steering as required. On-road that means ‘Comfort’, ‘Sport’ and ‘Individual’ modes, with off-road comprising ‘Trail’ and ‘Rock’. In the Comfort setting drive flows primarily to one axle for optimum energy efficiency.

Suspension is by double wishbones at the front and a De Dion-style live (rigid) axle at the rear. You’ve got the same adaptive-type set-up as per other G-Class models, so ‘Comfort’ and ‘Sport’ modes and of the many traditional G-Class traits this car exhibits, ride quality is one of them.

Even in Comfort you’ll find even little bumps and thumps making their way up into the seat of the pants and the cabin. It is after all a body-on-frame, ladder-chassis type vehicle and that’s not unusual.  

In terms of steering, it’s accurate and road feel is good. You’ve got 275-wide Falken Azenis FK520 tyres that are more on- than off-road focused. The car feels stable and nicely planted on the road.

The physical brakes are by ventilated discs front and rear, and the big rotors are the same size (353mm) all around. They work nicely and feel like a conventional set-up.

Regenerative braking kicks in as soon as you lift off the accelerator pedal. The powertrain is harvesting energy as the car decelerates and there are four levels you can adjust with the steering wheel paddles up to a quite aggressive level - not quite, but close to a single-pedal set-up.

Off-road, the G580’s ‘G-Steering’ system allows the wheels to turn at different speeds to induce slight ‘drift-like’ oversteer and tighten the turning circle. It works beautifully and the car’s fording depth is 850mm, a full 150mm more than internal-combustion G-Class models.

A three-speed off-road crawl function is adjustable to speeds as low as 2.0km/h, and the car is claimed to remain stable on sideways slopes up to 35 degrees. 

Torque vectoring is used to create ‘virtual diff locks’ and there’s a ‘low-range’ setting. Switch to the ‘Offroad Cockpit’ and data including gradient, lateral inclination, compass readings, tyre pressures and the selected G-Mode appear.

A ‘Transparent Bonnet’ function creates a virtual view of what’s approaching and passing under the front wheels to help the driver pick their way through steep ascents or declines.

For the record, the G580’s approach angle is 32 degrees, departure is 30.7, breakover is 20.3 and ground-clearance is 250mm.

And of course, with the wheels independently powered, the G580’s signature move is what Mercedes-Benz calls a ‘G-Turn’ but the rest of the world calls a tank turn.

If you encounter an obstacle that makes forward progress impossible, the system spins the left- and right-hand wheels in opposite directions so this brute can turn on the spot like an M1 Abrams. You can’t help but crack up laughing when executing this extreme party trick!

In terms of miscellaneous observations around ergonomics and the car in general, it has a 13.6-metre conventional turning circle. So if you’re not using the G Turn function in the car park be ready for a sizeable turning arc.

Also, those aero tweaks here and there seem to have had an effect. Wind noise, especially for such an upright, squared-off design is surprisingly modest. And overall, from a build point of view, this car feels as though it’s been carved from a solid piece of metal. In every aspect it presents as a quality item.

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.

As well as the usual passive safety features, the XM also hides the latest active safety gear. In fact, BMW reckons the XM has more driver assistance than any other M car before it.

Those elements start with the 'Driver Assistant Professional' which bundles active cruise-control with stop-go ability, steering and lane-keeping control, automatic speed limit assist and active navigation.

Parking assistance is also featured which incorporates a reversing assistance function, front, rear and panoramic camera views with a 3D view built in.

BMW’s 'ConnectedDrive' includes an emergency call function in the event of a crash or other emergency.

No ANCAP assessment so far.

The G580 is covered by Mercedes-Benz Australia’s five-year/unlimited-km warranty, which remains the standard offering in the premium part of the market and an eight-year/160,000km drive battery warranty.

Service intervals are every 12 months or 20,000km with service plan pricing available over three ($2645), four ($3980) and five ($4670) years. In approximate terms, each workshop visit will cost ‘around’ $900. Not exactly cheap, especially for an EV, but this is no ordinary electric vehicle.

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.