Mercedes-AMG S63 E Performance review: most powerful ever S is an incredible all-rounder

Mercedes-AMG S63 E Performance – have we lost the V8 while gaining a plug?

That’s a no, despite AMG having binned off cylinders elsewhere in its E Performance line-up. Like the Mercedes-AMG GT S E Performance, this S63 retains its V8. Specifically, a 604bhp 4.0-litre bi-turbo V8, held in place with active engine mounts. And yes, it has indeed gained a plug and a battery, with the V8 joined by an e-motor with 140kW (187bhp) and 1200 liquid cooled cells to power it.

Old world meets new with the S63 E Performance then, the combination of both meaning a system output of 791bhp. All that makes this the most powerful S-Class the company has ever produced, with that power underpinned by a faintly ridiculous 1,054lb ft of torque.

Those are some big numbers, how’s the weight?

Unsurprisingly, there's more of it, with AMG claiming a kerbweight of 2,595kg - about 550kg more than its predecessor in lightest form. A good deal of that is obviously down to the fitting of the plug-in hybrid system’s battery and rear-axle mounted motor – which has a two-speed transmission – as well as the addition of 4Matic+ four-wheel drive, a first for RHD S63s and certain to be necessary given that torque figure.

In comparison to the recent, hefty, C63 S E Performance, the S63’s weight gains actually don’t look too bad, particularly when you consider its retention of the V8 as well as the cabin opulence. And the big S63 shifts, too, with 62mph possible in 3.3 seconds on its way to its 180mph (if you’ve optioned the limiter increase from 155mph, as you would) top speed.

An AMG dragster then, or is there more to it?

It’ll certainly accelerate with the sort of ferocity that’ll see passengers spill their champagne while sitting in the fabulous rear seats, but there’s talent that comes along with that shocking pace. After slipping out of Santa Monica, California, silently gliding through the traffic on battery power alone – possible up to 20.5 miles – the quiet, twisting canyon roads rising above Malibu present a more interesting challenge.

Go on then…

Firstly, the addition of 4Matic+ has unquestionably changed the S63’s character a bit, as with all four tyres working it doesn’t feel quite as unruly as its predecessor could. That 4Matic+ along with AMG active roll stabilisation, rear-wheel steering, adaptive damping and air springs, the nine-speed transmission and the interaction of the hybrid/V8 and driver aids like traction, stability and more are all are configured via seven AMG driving modes. These encompass Electric, Comfort, Battery Hold, Sport, Sport+, Slippery and Individual, all of which are pretty self-explanatory.

After a good deal of explorative fiddling via a combination of twisting knobs and buttons on the steering wheel (tricky) and the large portrait central touchscreen (easier), we went Individual, settling on a combination of Comfort for the suspension – Malibu’s canyon roads ape our challenging, crumbling tarmac and the tauter suspension settings informing us too much of that – and Sport+ for virtually everything else.

Doing that sees the hybrid S63 cover ground with seriously impressive pace and composure. There’s agility that belies its 5.3m length, not to mention its bulk, and it's able to exploit its abundant output with surprising deftness. There’s precious little in the way of steering feel, but it’s light and accurate, and the rear-wheel steering shrinks the wheelbase to make it feel more E63 than S63 in length, turning in in a more sports, than luxury saloon manner.

The position of the electric motor and battery at the rear help here, balancing out its weight over the axles, the two-speed transmission attached to e-motor also meaning it’s always able to deliver with its peak torque of 236lb ft. Similarly, that e motor can work directly on the wheels and electrically operated limited slip differential to assist in stabilising the car, being quicker than a conventional system when doing so.

And still enough V8 sound loveliness to trigger a landslide?

Not really. You hear the V8, but it’s not particularly front of house even when you’ve asked it to be. This is an S-Class after all. What is impressive is the shove it all delivers and the ease by which it makes 791bhp exploitable. There are some provisos here, as the early car we drove did occasionally push through an unbecoming gearshift and have a braking/regeneration battle bleeding off the pedal at lower speeds playing out with a head-nodding judder. On asking AMG’s people we were told these are known calibration issues that have already been sorted for production cars.

That occasional judder aside the brakes felt mighty. The launch cars featured AMG's ceramic composite high performance option which felt well up to the task of hauling the big, weighty S63 down from the sizeable velocities it so easily gains. Should you wish to avoid using the brakes, you can set up the regeneration to the point it’s one pedal in its operation. At more sensible speeds, of course…

And when you’re not in a hurry?

It’s an S-Class, so peerless comfort, the best rear headrest cushions in the world and an ease and serenity that’s very appealing. There’s tonnes of tech within the MBUX multimedia system, too, and the stereo’s Dolby Atmos sound format brings new levels of clarity and detail to your music. This car’s need to be both performance as well as luxury saloon sees it gain a larger battery over its AMG GT relation, with the 13.1kWh here being over double the capacity. That allows the S63 E Performance its respectable 20.5 mile (33km) electric-only range.

The battery, developed with Merc’s F1 team, has its own direct cooling with 14-litres of non-conductive liquid flowing through it to maintain its perfect temperature for power delivery/regeneration, giving the S63 E Performance mighty, always accessible mid-range punch. It’s that, over ultimate battery-only range and outright economy, that's AMG’s goal with the hybrid system here, with the S63 E Performance rated at 53.4mpg combined, which is, erm, very optimistic given the numbers we saw on the trip computer.

Okay, I’m sold, how much?

£186,015 according to the UK AMG website, before you’ve ticked a single option box. Toppy then, but it’s the most powerful, most tech rich S-Class a lot of money can buy that has real duality of purpose. For that mount you might want for something that looked a little more overt over its lesser S-Class brethren. Though its bigger intakes, some AMG badges, bigger exhausts and vertical slatted grille and the loss of the upright Mercedes-Benz star up front – it being replaced by a flat AMG Affalterbach badge - do bring some added aggression. Very subtle. Again, it’s an S-Class, so that’s perhaps forgivable here.

Your chauffeur might need to be put on a part time contract because it’s appealing enough a drive to want to do it yourself rather than always sit in the back. An incredible all-rounder.