Mercedes-AMG GLS63 2021 63 4matic (hybrid)
launch-review

2021 Mercedes-AMG GLS 63 review: Australian first drive

Rating: 8.6
$255,700 Mrlp
  • Fuel Economy
    13L
  • Engine Power
    450kW
  • CO2 Emissions
    296g
  • ANCAP Rating
    N/A
Has Mercedes-AMG finally found a way to break the laws of physics? James bends time and space, with the seat massage on, in the mighty Mercedes-AMG GLS63.
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The use of technology to make the seemingly impossible, possible, has been called many things over the years; be it science-fiction, magic or perhaps just good old-fashioned engineering.

The 2021 Mercedes-AMG GLS63 is not just the latest, largest and most expensive weapon in AMG’s war against sensible family transport, it is also a showpiece for some of that magic and science-fiction, conveniently disguised as engineering, that can be only described as anything but old-fashioned.

Priced from $255,700 before options and on-road costs, the AMG GLS63 is a staggering $108,600 more expensive than the not-too-shabby Mercedes-Benz GLS450 ($147,100).

You do score the kitchen sink in terms of equipment though, including Nappa leather on the seats, door trims and dashboard, heated seats (and armrest) in the front and rear, the MBUX innovation package (which includes augmented reality navigation display and intelligent interior lighting), and to keep the brood comfortable there is not simply single, dual, tri or quad-zone; but penta-zone (it’s a thing) climate control.

Plus, where would we be in the S-Class of high-yield family weaponry without temperature-controlled cup holders?

Exterior components include AMG-specific front and rear bars, plus the enormous Panamericana vertical-slat grille, that lets everyone else’s rearview mirror know that vast quantities of the Earth’s atmosphere are soon to be consumed as you burble on by.

2021 Mercedes-AMG GLS63
Engine configuration4.0-litre twin-turbo petrol V8
Displacement4.0 litres (3982cc)
Power450kW at 5750rpm (+16kW EQ-Boost)
Torque850Nm at 2250-5000rpm (+250Nm EQ-Boost)
TransmissionNine-speed automatic AMG Speedshift TCT
Drive typeAll-wheel drive with variable torque split
Tare weight2710kg
Fuel claim, combined13L/100km
Fuel use on test15.9/100km
Turning circle13.1m
ANCAP safety rating (year tested)Not tested
Warranty (years / km)5 years / unlimited km
Main competitorsBMW X7, a train
MSRP$255,700
Options as tested$3900

Not content with all this though, the GLS63 includes a $3900 option of 23-inch AMG alloy wheels, in case the standard 22’s aren’t boss enough for you. It’s worth noting too, that these gigantic rollers, on their 325/35 ZR23 Michelin Pilot 4S rear rubber (with a hilarious load rating of 115 which supports up to 1215kg per tyre), don’t look out of place on the massive Merc.

Who would have thought 23-inch wheels would actually ‘work’ on a car?

Fun fact, they are around $600 a corner to replace which is much less expensive than I originally would have thought.

You can choose from ten colours with only the Designo options of Hyacinth Red ($1100) and Diamond White Bright ($1200) requiring extra expenditure. We drove a GLS63 in the always lovely Cavansite Blue, but think the new Emerald Green would be a particularly bold and striking choice.

Want more?

You can add a rear-seat comfort package ($2800) which extends the heated/cooled cup holder availability from just the pilot and co-pilot, and includes a removable tablet in the fold-down central armrest by which to control the MBUX infotainment system.

I will say, it is nice, but you would have to really love your kids to give them that level of control over the car’s music selection.

You can add a towbar (3500kg rating) for $1900, and even lavish the interior ($4200) and engine bay ($2800) with actual carbon fibre.

The interior is exclusively black, but you can go in for an extra $1400 to add a quilted-look AMG-Style trim in Macchiato Beige. Perhaps leave this one for after the kids have left home.

2021 Mercedes-AMG GLS
Length5243mm
Width2030mm
Height1837mm
Wheelbase3135mm
Ground clearance203mm
Weight (Tare)2710kg
Wheels/tyres285/40 R23 front / 325/35 R23 - Michelin Pilot Sport 4S

As you may have surmised, the GLS63 is no less husky that its ‘regular’ brethren, with the unique AMG styling actually taking up an even bigger hole in the world (it’s 24mm longer than a GLS540), and all the extra goodies adding a little bit of bulk (54kg) to the big SUV.

That’s OK though, as under the bonnet is the always-fun-at-parties AMG 4.0-litre twin-turbo V8 with a rollicking 450kW and 850Nm up its sleeve. That 74 per cent price premium over the ‘450 makes more sense now, as the outputs are up 67 and 70 per cent respectively over power and torque figures on the GLS’ser (see what I did there?).

However, I introduced this review with a tease of magic, and herein lies the six-three’s first big party trick.

The V8 is connected to an AMG Speedshift 9-speed TCT (torque converter) automatic transmission, with a 48-volt mild-hybrid system shoved in between.

This EQ Boost ‘starter-alternator’ not only acts as a generator to help with smooth engine start, stop and restart, and to power some of the vehicle’s ancillary systems, but also gives the V8 a bit of an extra tickle of oomph under short, but heavy demand situations.

With an additional 16kW (for 467kW total) and 250Nm (for 1100Nm total) to add to the physics mix, the EQ-Boost enables the giant SUV to shift all 2.7-tonne, plus passengers to 100km/h in just 4.2-seconds.

Even when relying only on the hot-vee twin-turbo, the GLS offers exceptional response throughout the rev range. To have 850Nm underfoot from just 2250rpm, all the way to 5000rpm, which is just shy of the peak power point of 5750rpm, makes the GLS infinitely flexible.

Ease into merging traffic, and you have response. Need to carry momentum up a hill, and you have response. Want to quickly overtake a slower B-double, and you have response.

There’s no need to issue a chain of commands from Kirk to Sulu to Scotty, your right foot can request warp factor 9 and the GLS Enterprise will respond faster than you can think of a cheesy Shatner-esque quote about Klingons.

Perhaps the only downside is that the usual antisocial exhaust pops and crackles that we’ve experienced on other ’63 SUVs are somewhat muted. Probably not a bad thing for your neighbours though.

It’s pretty impressive, given the thing is the size of a small apartment (building), and sure, doing this will see you reach and hold at the maximum displayed fuel consumption of 30L/100km, but once you’ve launched the ICBM-63, you can enjoy it’s second amazing skill.

In-flight, the big guy is quite economical.

I know everything is relative, and a near-on-3-tonne V8 rectangle is never going to be matched with a Prius, but in terms of what it is and what it does, the GLS doesn’t need to feel tethered to its closest petrol station.

When cruising, event at urban speeds, the V8 will idle a bank of pistons and run as a four-cylinder. You even get a little light on the dash to let you know what’s going on. Plus, the transmission will enable a free-rolling ‘coasting’ mode to further reduce the engine’s thirst.

Mercedes claims a combined cycle use of 13L/100km, which is actually up on the claim of 12.3L/100km for the previous-generation GLS63, but in reality, is much more achievable. Where the old car would idle away in the 20-something range, I saw an average of 15.9L/100km on a run which was anything but a hypermiling attempt.

In fact, the use on a short urban run in the ’63 was similar, if not slightly better, than what I’ve seen in the GLS450 long-termer.

All of this is really just a guilt minimisation strategy though, as not one person is paying $100k more to brag about being able to deactivate cylinders. No, the GLS63 is most at home when chewing up blacktop as a very rapid and comfortable mass transit system, and it leads me to the car’s third and most impressive magic trick.

Like Marvel’s Ant Man, the AMG technicians have discovered a way to simply shrink the atoms and protons that make up the GLS63, and again it all comes back to that 48-volt system.

Dynamic engine mounts brace the V8’s lateral movement in the engine bay, limiting the amount of weight transfer under cornering loads.

More impressively though, is the active roll stabilisation that limits the amount the car physically tilts through corners.

2021 Mercedes-AMG GLS63
ColourCavansite Blue
Price (MSRP)$255,700
Options as tested$3900
Servicing 3yr$3050
Servicing 5yr$4550
ANCAP safety ratingNot tested
Warranty5 years / unlimited km

In Comfort mode, the air springs provide a compliant and rather lush-feeling ride, but along twistier stretches, still translate a wobble into the cabin as the car moves around.

Switch to Sport Plus (whoever uses Sport when Plus is a choice?) and things tighten up somewhat to provide a firm, yet never uncomfortable ride, and body control that can almost be described as nimble.

As you tip it into a tight left-hander, the car lifts and braces the right side, making the whole movement somewhat diluted, and inherently more pleasant for your passengers.

The 4Matic+ all-wheel-drive system operates with an imperceptible variable torque split that helps move power to where you need it the most, making direction changes both under and off throttle, feel sure-footed and confident.

Like the incongruous nature of a flexible and fast-moving sumo-wrestler, the bulky weight of the GLS shrinks around you, with the car now feeling something like a much smaller GLC. You carry speed through corners and power along straightaways with a strength and agility that belies the voluminous nature of the baddest big Benz.

The only thing that will return you sharply to reality is when another vehicle comes the other way and you are swiftly reminded that you take up a size-13 footprint, rather than a more svelte size six.

The 2021 Mercedes-AMG GLS63 is the S-Class of SUVs in the way it dishes up technology, comfort and all-round luxury appeal.

The fact it is also the E-Class of SUVs in terms of its ability to act economically, the C-Class of SUVs in the way that it feels on the road with the trick suspension, perhaps the V-Class of SUVs if you fold all the seats down – and maybe the A45 of SUVs in the way it performs and entertains in a way that nothing of its shape and size has any right to do so – only highlights the multi-faceted nature of the AMG behemoth.

Yes it is expensive. Yes it is extravagant.

And yes, it really is largely pointless, given that most of these will only ever be used to run around town – but the GLS63 is an impressive output of what can be done when engineering technology surpasses what we can even imagine from both science-fiction and magic.