Mercedes-AMG GLE63 vs BMW XM

What's the difference?

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’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.

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.

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.

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.

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 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.

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.

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.

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.

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.

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.

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.

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.