In the world of monster trucks like the new 2021 Mercedes-AMG GLE 63 S, six centimetres is not much chop. Except, it is to Mercedes-AMG, because it hopes that small distance will dramatically split both the new GLE 63 S wagon and its coupe sibling on personality.

The fourth-generation GLE is the first time the brand has built the body styles on a different wheelbase that is, you guessed it, six centimetres longer for the wagon. It hopes to cater to buyers with a more specific product, further differentiating between performance and practicality.

2021 Mercedes-AMG GLE 63 S review

This new powertrain marks two milestones. Firstly the new GLE 63 S engine officially replaces the old loveable 5.5-litre twin-turbo V8 known as the M157, which featured in the first-generation E63 S and GLE 63 S. Secondly, the new GLE 63 S is the first go at electrifying a flagship AMG model. Let alone one with 450kW and 850Nm.

The mild-hybrid technology works similarly to the system already found in the E53 Coupe. An alternator motor wedged between the engine and transmission can deploy an extra 16kW and 250Nm when needed. It can also help kick the engine over during start-stop operation, charge batteries, aid engine-off sailing and control idle speed.

The electric assistance does not necessarily equal more power, however, according to the spec sheet. Although the new GLE 63 S produces 850Nm from 2500rpm to 4500rpm, overlapping with the electric low-down shove to theoretically combine for 1100Nm, AMG refuses to quote a combined torque figure.

2021 Mercedes-AMG GLE 63 S review

That reduction is alarmingly small given the mild-hybrid system and the fact this particular V8 can shut down a bank of cylinders to curb its thirst. But all these technologies add more than convenience.

Measuring 4939mm long, 2010mm wide, and 1730mm tall, the new GLE 63 S has grown in length and width. It now weighs 2345kg, 75kg more than the old one. Part of the increase comes from new active anti-roll bars and engine mounts.

Unsurprisingly, the price for a GLE 63 S has grown as well. At $220,600 before on roads and options, the new GLE 63 S is $29,984 more expensive than the old 5.5-litre version from 2016. It also costs more than the BMW X5 M Competition ($212,900) or the Audi RS Q8 ($208,500).

2021 Mercedes-AMG GLE 63 S review

Exclusive additions include AMG Nappa leather in Magma Grey/black and 21-inch AMG wheels. It also scores AMG Active Ride Control, temperature-controlled cup holders, four-zone climate control, power closing doors and seven metallic paint options above a GLE 53.

Other standard equipment includes the Exclusive Package, which adds extra trim elements on the back of front seats while adding heating and ventilation to them as well. It also adds wireless charging, a panoramic sunroof and Burmester sound.

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Inside it scores an AMG-optimised MBUX infotainment system on dual widescreen displays, loaded with smartphone mirroring. They sit behind an AMG Performance steering wheel finished in GLE 63 S-specific microfibre. It also includes a lockable compartment and multi-contour front seats with massage functions.

The GLE 63 S also benefits from a full suite of active safety features, like lane-keep assist, lane departure assist, active cruise control, AEB, active blind spot assist, an exit warning function and active Stop and Go assist. ANCAP has rated it five stars.

2021 Mercedes-AMG GLE 63 S review

These include an interior carbonfibre package ($3900) that adds carbon trim to the front workstation and steering wheel or an Energizing Package Plus that includes cabin air purification with fragrance and armrest heating for $3200.

Bored kids? An Entertainment package with MBUX rear seat TVs and wireless headsets costs $6300. An Innovation package with Augmented Reality navigation – which overlays the front-facing camera view with graphics showing your direction – also includes Interior Assist for $800.

2021 Mercedes-AMG GLE 63 S review

All these options represent almost $30,000 and take a fully loaded GLE 63 S above $275,000 driveaway. Expensive? That depends on how your trust fund performed last year.

Either way, the GLE 63 S comes with a five-year unlimited-kilometre warranty, beating the BMW 80,000km five-year offer and Audi’s unlimited-kilometre three-year program. Service intervals are slightly more strict for 63 models, set at every 12 months or 20,000km compared to 25,000km for all other Benz models. Capped-price servicing lasts for three years.

Unsurprisingly the GLE cabin in 63 S trim is pure luxury. From the panoramic sunroof to the form-hugging seats with adjustable bolsters, it is class. Even the rear seats offer four-zone climate control and two USB-C ports.

2021 Mercedes-AMG GLE 63 S review

The rear boot offers 630L worth of cargo, which grows to 2055L after folding away the rear row. Under the boot floor lies a space-saver wheel and goo kit for punctures. You can also hit a one-flick switch that lowers the rear suspension when loading items into the boot.

The MBUX dual widescreen displays offer more information than you would ever need, especially now that it features an AMG Track Pace app. The head-up display is just as rich with information, offering plenty of customisation.

2021 Mercedes-AMG GLE 63 S review

The suspension, anti-roll bars and active engine mounts link to the drive modes, of which there are seven (!) comprising Comfort, Sport, Sport Plus, Individual, Race, Trail and Sand. The latter two optimise the car’s smooth nine-speed automatic transmission and transfer-case based all-wheel-drive system to work on slippery surfaces, while the air suspension raises 55mm.

The more sporting drive modes instead lower the suspension 10mm, hunkering down on standard 21-inch wheels. Mercedes-AMG’s big-engine SUVs are known for their punch rather than their sidestep and nothing has changed for the new 63 S. Active roll bars cancel out roll to a degree and equal good directional stability through long sweepers. And the variable-ratio steering rack points true, even on decreasing radius bends.

2021 Mercedes-AMG GLE 63 S review

Although it booms down low with the exhaust open, the engine’s sweet-revving nature equals a robust, full-bodied roar on the way to its 7000rpm redline. The push forward is tremendous in the mid-range, especially when the electric motor is chipping in. The sprint from zero to 100km/h is claimed to fall in 3.8 seconds.

You are occasionally confronted by the tremendous weight the engine has to battle. For instance, even the unbelievably grunty twin-turbo V8 can struggle to get going in fifth gear under 3000rpm.

The upside is an all-wheel-drive system and electronically controlled rear LSD that never runs out of grip on Continental tyres that span 275mm wide up front and 310mm wide out back.

2021 Mercedes-AMG GLE 63 S review

Overall, what’s most likeable about the GLE 63 S is its honesty. Although it’s nowhere near as agile as something like a Porsche Cayenne GTS or BMW X5 M, you can sense it doesn’t care. Instead, it concentrates on what a five-metre SUV with a twin-turbo V8 should.

Some of that includes hinging its personality on the idea of a twin-turbo V8 in a two-tonne SUV. Thankfully, electrification hasn’t softened the monster within the maddest GLE Mercedes sells. But its strengths also include the serious luxury, passenger comfort and long-legged cross-country ability we expect.

2021 Mercedes-AMG GLE 63 S review

The only thing missing is simplicity. We suspect that, like the driver who is surrounded by all those buttons, the GLE 63 S itself is overwhelmed by the technology.

Then again, when it comes to twin-turbo V8 luxury monster trucks like this, pragmatism is not as important.

Verdict (7.5/10)

Likes: Prodigous mid-range grunt, directional stability, luxury vibe, room and storage, decent ride

Dislikes: Slow steering at low speeds, obvious weight, porky handling, complex front workstation

Specifications

Body: 5-door, 5-seat SUV Drive: all-wheel Engine: 3982cc V8, DOHC, 32v, twin-turbo (with e-motor) Bore/stroke: 83.0 x 92.0mm Compression: 8.6:1 Power: 450kW @ 5750-6500rpm Torque: 850Nm @ 2500-4500rpmE-motor: 16kW/250Nm Fuel consumption: 11.5L/100km (combined/claimed) Weight: 2270kg Power/weight: 198kW/tonne Transmission: nine-speed automatic Suspension: A-arms, air dampers, active anti-roll bar (f); multi-links, air dampers, active anti-roll bar (r) L/W/H: 4954/2018/1782mm Wheelbase: 2995mm Tracks: 1693/1720mm Steering: electrically assisted rack-and-pinion Brakes: 400mm ventilated drilled discs, six-piston calipers (f); 360mm drilled ventilated discs, single-piston calipers (r) Wheels: 21 x 10.0-inch (f); 21 x 11.0-inch (r) Tyres: 275/45 R21 (f); 310/40 R21 (r) Continental SportContact 6 Price: $220,600 ($246,278 driveaway)