Mercedes-Benz GLS-Class vs Mercedes-Benz GLC-Class

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…

Like I said right from the start, this new, hybrid version of the AMG GLC63 is technically superior to the model it replaces in every meaningful way. It is faster, more powerful and more fuel efficient and therefore a better performance SUV than the model it replaces.

Is it a better model than the one it replaces? Ultimately that will come down to how much stock you put into the soundtrack and your feelings on an AMG not powered by a V8 engine.

Because if you can see past that, then the AMG GLC63 is an absolutely fantastic performance SUV. Not only does the new powertrain make it faster in a straight line, but the chassis is very well-balanced, making for an engaging driving experience.

For those who can look past the smaller engine they will be rewarded with an incredibly fast and rewarding-to-drive member of the AMG family.

Note: CarsGuide attended this event as a guest of the manufacturer, with travel, accommodation and 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 GLC63 is unmistakably an AMG from the moment you first lay eyes on it. That’s thanks to the AMG-specific elements, starting with the grille with vertical strikes and the AMG crest on the bonnet; which is now a signature item for the performance sub-brand.

The GLC63 is also fitted with the Night Package II design kit; this adds a darkened grille and black chrome badging to further enhance its visual appeal.

The AMG-specific alloy wheels and more aggressive stance do mean the GLC63 stands out from the rest of the GLC range, helping it look fast even when it’s standing still.

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.

Inside the GLC63 is clearly a derivative of the rest of the range, with its C-Class-inspired design and layout, but there’s enough AMG-specific elements to ensure it looks and feels special. This starts with the AMG steering wheel, which comes not only with a thick rim wrapped in Alcantara, but also some AMG special dials to adjust the various performance settings for the powertrain, suspension and transmission.

Then there are the AMG-specific seats, which look good and offer good support for the driver and front seat passenger. The rear seats offer decent space for what is a mid-size SUV, with room enough for two adults or teenagers or three smaller kids.

Those in the back aren’t particularly well looked after though, with only rear air-con vents and small door pockets but no USB charging ports or other small item storage.

The boot is 590 litres, down from 620L in the rest of the range, thanks to the addition of the rear-mounted electric motor. There’s also no room for the temporary spare the rest of the GLC range gets and instead you have to make do with a puncture repair kit.

The power and torque figures aren’t the only numbers that have risen sharply, with the GLC63 clearly impacted by a double whammy of inflation and the usual new-car price rise.

The GLC63 now starts at more than $191,814 for the SUV and $198,415 for the Coupe, which represents a nearly $30k increase over the old V8-powered model, which was priced at $164,600 just two years ago. Even for luxury car buyers that’s a big jump, especially when you’re trying to convince people of the merits of the four-cylinder powertrain. 

That also means it's more expensive than all of its key competitors, including the BMW X3 M Competition, Maserati’s Grecale and the outgoing, petrol-powered Porsche Macan GTS.

To help explain some of this price increase Mercedes-Benz Australia has opted for a high level of standard specification for local cars. Standard equipment includes 21-inch alloys, AMG composite braking, a panoramic sliding sunroof, a unique AMG steering wheel, power-adjustable sports seats in Nappa leather, a head-up display, dual-zone climate control, wireless smartphone charging and a Burmester 3D Sound system.

Also included is the AMG Track Pace suite, for those who want to unleash their GLC on the racetrack.

There’s also a limited run, AMG Edition 1 Package available too, for an additional $12,900. On the outside you get Manufaktur graphite grey magno paint, foiling with colour gradation and large AMG logo on the sides, an AMG Aerodynamics Package, unique alloy wheels with Edition 1 and AMG branding, yellow brake calipers and an AMG fuel filler cap in silver chrome with AMG lettering. 

Inside there’s AMG Performance seats, AMG Nappa leather in black with yellow contrasting stitching, AMG illuminated door sills,  carbon-fibre AMG trim highlights, yellow seat belts and a unique AMG Performance steering wheel wrapped in carbon-fibre and microfibre.

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.
 

This is what lies at the heart of the AMG GLC63’s success or failure. As I mentioned at the beginning, the previous generation’s 4.0-litre twin-turbo V8 has been replaced by an F1-inspired plug-in hybrid powertrain.

But don’t think that means AMG is suddenly focused on efficiency over performance. When AMG says the powertrain is inspired by the brand’s success in Formula 1 racing, what it means is the battery and electric motor provides a significant performance boost to support the internal combustion engine, not just save fuel.

To that end the combination of the turbocharged 2.0-litre four-cylinder petrol engine and the rear-mounted electric motor produces an impressive 500kW and 1020Nm. That’s a massive jump over the 375kW/700Nm made by the outgoing V8.

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.

Mercedes makes no secret that the battery is designed for performance, not saving fuel. It only has a 14km EV range but can recharge quickly on the move to provide a power boost when needed.

But despite all that, the GLC63 is actually significantly more fuel efficient than the old V8, using a claimed 7.3L/100km, which is a massive 4.9L/100km improvement over the old model. Although, on our day-long test drive we didn’t manage to come close to that claimed figure and instead saw returns around 11L/100km, albeit after a lot of spirited open-road driving.

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.

Anyone who still believes in the adage ‘there’s no replacement for displacement’ hasn’t driven a modern turbocharged and hybridised engine. The GLC63 is a demonstration of the metaphorical and literal power of modern technology, combining an extremely efficient and potent internal combustion engine with an electric motor to make enormous real-world performance.

To be blunt, the GLC63 feels like a rocketship out of corners, launching with a ferocity and relentlessness the old V8 simply can’t match. It shouldn’t come as a surprise, a mid-size SUV with 1020Nm was always going to have plenty of performance, but even so it’s a shock to the system every time you give the GLC63 full throttle. Officially AMG claims it takes just 3.5 seconds to run 0-100km/h and has an electronically limited top speed of 275km/h - mighty impressive figures for a five-seat mid-size SUV.

To help get all that torque to the road, AMG deploys torque distribution technology that allows for it to be split an even 50/50 front/rear all the way to 100 per cent to the rear tyres.

Other technologies deployed to enhance its handling include AMG Ride Control suspension with adaptive damping and rear-axle steering. There’s also eight AMG Dynamic Select driving modes and four AMG Dynamics settings (Basic, Advanced, Pro and Master), so it’s a complex vehicle that is designed for the enthusiast.

While it’s easy to drive around town, once you get out on the open road you can really get a sense of the GLC63’s performance potential. Beyond just its powertrain the suspension offers good body control and the rear-axle steering helps it feel agile and responsive. 

It’s not perfect though. At times the complexity of the system does lead to some hesitation when you put your foot down. It certainly lacks the linear power delivery of the old V8 and makes for a slightly trickier driving experience at times.

As for the sound, which is one of the biggest elements missing from the V8, Mercedes has added AMG Real Performance Sound, which features a pressure sensor in the exhaust that picks up on the engine note and plays it through the speaker system. It certainly helps make for a louder, more noticeable engine noise, but it still sounds more like an A45 than the previous GLC63 and for many would-be buyers, that’s a major turn-off.

The GLC63 comes standard with a comprehensive suite of safety features including 'Distronic' (Mercedes’ name for adaptive cruise control), 'Active Lane Keeping Assist', 'Blind Spot Assist', 'Traffic Light Assist' and 'Adaptive Highbeam Assist'. It also includes Mercedes’ 'Pre-Safe' accident anticipation system - which pre-tensions the seat belts and will even play a white noise to protect your ears if it senses a crash is imminent.

A parking system that includes a 360-degree camera and active parking assist is also included.

The GLC range was awarded a five-star ANCAP rating in 2022, which pre-dates the latest testing protocols, so doesn’t provide a like-to-like comparison for vehicles tested after that date.

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.

The GLC63 is covered by Mercedes Australia’s usual five-year/unlimited kilometres warranty.

As for maintenance, Mercedes offers service plans, spanning three to five years. Three years will cost you $5025, $6455 for four years and five years is priced from $7180. Servicing intervals are 12 months or 20,000km, whichever comes first.