The S65 remains on the top of rung powered by a twin-turbocharged, 6.0-litre V12 developing a mammoth 621bhp and 737lb ft of torque. Overall it helps the 12-cylinder AMG reach 62mph 0.1 sec faster than the S63, but at the cost of drinking its fuel at a far more rapid rate. In terms of its place in the market, none of its competition can get close to the power output from the S65, bar the all-paw BMW M760Li.
An AMG S-Class is still all about the luxury
But as good as those engines are, what actually dominates is the sense of money-no-object opulence. Mercedes has left virtually no stone unturned in its pursuit of ultimate luxury. Almost every feature is electrically powered, double-glazed or internet-connected. Most of the facilities are operated via a 12.3in colour screen.
If anything, rear passengers are served even better, with enormous legroom afforded by the long-wheelbase-only chassis configuration. The huge range of options includes a pair of individual seats – a £5000 extra.
A browse through the standard equipment list won't leave many feeling short changed either, with both models getting the same level of equipment as an AMG Line trimmed S-Class. The S63 gains 20in alloys, parking sensors, a reversing camera, adaptive LED headlights and a beefy bodykit fitted as standard on the outside. Inside there is a Nappa leather upholstery, electrically adjustable front sports seats, ambient interior LED lighting, a Burmester audio system and Mercedes' COMAND infotainment system, which includes a two 12.3in screens, sat nav, DAB radio, Bluetooth and USB connectivity.
The S 65 comes electrically adjustable, ventilated and reclining rear seats, a Nappa leather headlining and a 3D Burmester surround sound system. However, the luxury doesn't end there as a wealth of optional extras can certainly endow your AMG S-Class with as much luxury as you or your wallet can stomach.
Unleashing the growling AMG on the road
Out on the road, one of the impressive aspects of the S63, we tried, is its Magic Ride Control, which uses a camera to scan the road ahead to prime the adaptive suspension for the optimum ride and body control. The system, which is standard, works intuitively and really does iron out most undulations, but high-frequency scars can still be felt.
You can deactivate it by switching to Sport mode, and if you’re looking to really dial performance up a notch, you’ll want to. With the full potential unleashed, you can enjoy masses of grip along with the restrained growl from that 603bhp V8.
At speed the S63 feels far narrower than its 2.1m girth suggests, and once you overcome the initial over-assistance, the steering allows you to put enough faith in it to exploit the AMG-specific chassis setup.
It feels more planted at high speed than a Jaguar XJR 575, thanks in part to a 100kg weight loss over its predecessor, but the Jaguar still shades it in terms of outright fun. The AMG offers the better blend of refinement and engine note; rhythmic at low speed and bellowing with restraint as it approaches the 6500rpm redline. The engine note is delightfully muted, although always there. If you want NASCAR thrills, then the equally powered but all-paw E63 would be a better bet.
Power is commuted to the rear wheels through a seven-speed Speedshift MCT automatic gearbox. It provides snappy shifts, but – as with the rest of the car – never at the expense of sublime comfort.
The Mercedes-AMG S63 wants for nothing, although there is, predictably a myriad pricey options. But it is hard to think of the S63 AMG in pragmatic terms.
The truth is, if you want to travel in unparalleled comfort and refinement, then an S 350 or an S 500 would be slightly better. And an E 63 AMG would better serve those looking for traditional super-saloon thrills, and can be had in wagon form too.
However, the S63 AMG is simply one of the world’s best cars with one of the world’s best performance engines. And it’s hard to argue against it.