Mercedes-Benz GLS vs BMW M5

What's the difference?

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…

Let’s get one thing out of the way: the new M5 is a very good car. Considering the emissions limitations and size increase of its base model, it is an impressive bit of engineering. 

What’s trickier is deciding whether the new car is really better to drive. Less edgy but supremely comfortable and quiet; BMW leaned into the daily usability of the plug-in hybrid M5 rather than amping the petrol-electric system for maximum thrills. And do you know what? That’s fine with me. 

The new M5 still performs on road and track and does an incredible job of hiding its weight (most of the time). Perhaps the G90 is a little more Audi RS6 than F90 in its demeanour but some would argue that’s no bad thing. 

The concept of the BMW M5 is not static, it evolves with the times, and the G90 is no exception. Expect future Competition and CS variants to unlock some extra lunacy. 

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

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.

The M5’s raw size is what you notice first. The G90 M5 is a whopping 113mm longer, 67mm wider and 37mm taller than the car it replaces, with the wheelbase stretched 24mm.

It is also the most pumped M5 yet, compared to a 520i it is 70mm chubbier at its flared wheel arches. The ‘M5’ insignia on the C-pillar means you’ll know this is the fast one. 

Presence is not in question, then, but beauty? Not the right word. The G90 makes its predecessors — especially the original ‘E28’ — look demure. 

The cabin layout builds on the concept debuted by the iX electric SUV, with twin integrated screens and focus on technology and minimal buttons. Materials are mostly high quality and feel fitting for the M5’s asking price.

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.

BMW has persevered with its twin-screen, minimal-button approach for its 'Operating System 8.5' in the M5. 

The 14.9-inch central touchscreen is bright, responsive and high resolution but the software remains a little strange. The main interface is classy but when looking for settings to adjust you’re presented with a Windows 95-esque panel of small square touch targets. It’s not intuitive. 

Wirelessly mirroring Apple CarPlay or Android Auto works a treat, at least. Digital climate controls keep temp adjustment persistently on screen and a shortcut to fan speed. The nipple-like vent direction adjustment grows on you, as do the digital vent sliders. 

The 12.3-inch digital driver’s display still doesn’t have the freedom of customisation and clarity of Audi’s interface. 

The M5 has two cupholders, a deep central storage cubby, door bins that swallow two 600mL plastic bottles and twin wireless charging pad that resolutely grips smartphones even under the sort of tummy-churning G-Forces this M5 can manage. 

Setting the M5 apart from the regular sedan is a unique centre console bunching 'M Drive' modes, 'M Hybrid' modes and other shortcut functions together next to the gear toggle and M-engraved crystal 'iDrive' controller.

Comfortable front seats are power adjustable with in/out, up/down lumbar support and have two memory positions. 

The 5096mm long M5’s back seat is very spacious. Headroom is good for those beyond 182cm (six-foot), the bench is extremely supportive, while leg and toe room are adequate.

A fold-down centre armrest has two cupholders and there are USB-C charge ports in the back of each bucket seat for a total of four. 

You can buy an accessory mount that holds tablets or smartphones for rear seat passenger entertainment, too.

When you look in the boot, BMW offering a Touring version of the latest M5 makes even more sense. The load aperture is big but the usable space is narrow; the sides intrude on load space. 

The 466-litre space will make fitting suitcases for an airport run tricky and, even with the 40/60 split-fold rear bench, you will struggle to fit a bike in the back. There’s no spare tyre, either.

The last M5 was well equipped but the new car is wanting for nothing. Australian cars have just about every option for $259,900, before on-road costs.

Australian M5s wear staggered 20-inch front and 21-inch rear alloy wheels paired with standard metallic paint, 'M Carbon Exterior' package (including carbon roof and rear lip spoiler), adaptive LED headlights and BMW’s 'Iconic Glow' illuminated kidney grille surrounds. 

Keyless entry, a heated steering wheel, heated and ventilated front seats, interior camera, powerful 18-speaker Bowers & Wilkins sound system, M seatbelts, four-zone climate control and a power tailgate are the cabin highlights. 

Optional extras are thin on the ground; you can choose from (eight) no-cost paint colours and all manner of 'Individual' shades (from $4100), four interior trims including classy 'Dark Oak' wood and four leather colours. There’s classic black ‘Merino’ leather, or you can have it dyed with a mix of 'Silverstone', red or 'Kyalami Orange'. 

Aside from that, the only major option is carbon ceramic brakes at a staggering $18,500, and an M5 Touring wagon costs $263,900. 

Though the M5 is more expensive than Audi’s closest rival, the RS6, the gulf isn’t huge considering you get a lot more punch in the BMW. Mercedes-AMG does not have an E-Class answer, yet.

Good value, then? Well, an equally potent Porsche Panamera is twice the price. So yes, in a sense.

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.
 

Unlike the Mercedes-AMG C63, BMW has kept the M5’s eight-cylinder heart and this has proven to be a good decision. 

The 4.4-litre twin-turbo petrol engine has been optimised with “a cross-bank exhaust manifold and optimised oil separation”, says BMW.

The V8 spins to 7200rpm though it isn't a screamer, outputting a full-bodied 430kW (5600-6500rpm) and 750Nm (1800-5400rpm).

Augmented with a transmission-mounted 145kW electric motor that can produce up to 450Nm, thanks to pre-gearing, maximum combined outputs are 535kW and 1000Nm. 

Weight blunts punch, though, so despite nearly 100kW and 250Nm more, the new M5 is a tenth slower to 100km/h than its predecessor (claimed), at 3.5 seconds for the sprint.

You can thank a 220kW/tonne power-to-weight ratio, worse than the old car's 233kW/tonne figure. The new G90 claws some time back with brute force, hitting 200km/h in just 10.9 seconds and goes on to a limited top speed of 305km/h.

You can choose from five powertrain settings, starting with 'Electric' and 'Hybrid' for everyday use, while 'eControl' lets you store battery power for urban use.

'Dynamic' provides the best balance, says BMW, while 'Dynamic Plus' is like a qualifying mode. Think maximum combined punch for up to 10 minutes, at which point you’ll have drained the battery. 

Driving in pure electric mode, the take-off can be a little jerky but the quietude and decent power make it pleasant. Power sources are combined expertly in Hybrid and giving it some stick in Dynamic is more than enough to make your passengers feel queasy.

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.

Electric-only range is rated up to 69km in WLTP testing, but the 18.6kWh battery is more likely to give you around 60km in real-world driving. It can be topped up in about two hours using an 11kW AC charger, or overnight on a three-pin socket. 

BMW includes both Mode 3 (public) and Mode 2 (home) charging cables with the M5. 

The M5 uses 3.2L/100km of 98 RON premium unleaded in ADR testing, corresponding to just 72g/km of CO2, so it should sail through the first rounds of Australian emissions regulations. 

Indulging in what the V8 has to offer sees that consumption spike, though. An enthusiastic road drive saw the M5 gulp 12.4L/100km, according to the trip computer.

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.

The three M5 elements start with daily usability. We trundled out of Bathurst in electric mode, with the adaptive dampers (and other myriad settings) in Comfort. 

The M5 has steel springs, double wishbone front suspension and a five-link rear axle, all of which has been heavily reworked by the boffins at M. Naturally, the ride is firm, though in Comfort the body moves through its motions smoothly. 

The M5 is an effortless tourer, its eight-speed automatic shmoozing through ratios as it climbs and descends steep gradients. Wind and tyre noise insulation is good on coarse chip tarmac, though a bit more burble from the V8 would be appreciated. 

The M5 has nine adjustable parameters to wake it up: 'Drivetrain', 'Energy Recovery', 'Drivelogic' (gear shift aggression), 'Chassis', 'Steering', 'Brake', 'M xDrive', stability control settings and 'M Sound'. Favourite settings can be stored to the wheel-mounted M1 and M2 buttons. 

With the dampers still in Comfort the M5 remains fantastically capable with power delivery from the xDrive mighty rewarding on corner exit. Sport dampers sharpen the experience up further, amplifying the M5’s surprising agility. Thank the rear-wheel steer for this big sedan’s switchback performance. 

Step beyond the limit of grip, brake too late, or get on the power too early, though, and the M5’s mass reveals itself rapidly. It doesn’t help that the accurate steering is devoid of feel. The brake-by-wire pedal is too numb and light, as well, making it tricky to judge grip levels on the road.

Feel is less of an issue on a dry Mount Panorama circuit, where the M5 turns out to be a total pussycat. The all-wheel drive, consistent dynamics, strong brakes and well-tuned stability control make for an approachable but seriously fast sedan.

The responsive transmission will hold gears to redline and is eager on the downshift in its most aggressive setting while tactile shift paddles make commanding ratio changes yourself that bit more engaging. 

Prodigious punch out of corners is matched by the impressive consistency of the carbon ceramic brakes. The M5 pulled up for The Chase every time with minimal fuss, even from above 250km/h.

Similar credit goes to the 285mm front and 295mm rear Hankook S1 Evo tyres which remained consistent and predictable all day despite reaching temperatures over 130 degrees, according to the tyre pressure monitor.

The regular BMW 5 Series range scored a maximum five stars in 2023 ANCAP safety testing but this does not apply to the M5.

The M5 features nine airbags and a host of active safety systems, including auto emergency braking (AEB), blind-spot monitoring, rear cross-traffic alert, lane-keep assist, auto parking and speed limit assist. 

Lane-keep can easily be turned off via two taps but the other systems require more menu navigation, though are mostly unintrusive. A 'Track' mode disables lane-keep, AEB and other systems along with switching the central display off. 

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.

In Australia, BMW has moved to match other manufacturers in offering a five-year/unlimited kilometre warranty on all its cars. 

Servicing is recommended on a condition basis, with the M5’s multimedia system prompting a visit to the mechanics. BMW offers pre-paid service packs for five years/80,000km at a price of $5059 for the basic offer and $8152 for 'Inclusive Plus', which covers brake pad and rotor replacements. 

It is expensive next to a regular 5 Series but when you consider the purchase price and performance level, the M5’s service pricing is not astronomical.