In the same way that the Mercedes-Benz S-Class is the flag bearer for the Mercedes range, the AMG-tuned S-Classes are the pinnacle of that luxurious model line. It retains the kit you’ll find on ‘lesser’ S-Class models, but turns up the dial with that stunning, hand-built 5.5-litre twin-turbo V8 and 6.0-litre V12.
The 'entry-level' as much as a 5.5-litre V8 motor can be, the S 63, develops 577bhp at 5500rpm, just 1000rpm shy of its redline, while peak twist is 663lb ft, which arrives at 2250rpm and plateaus until 3750rpm. It's good for a 4.4sec 0-62mph time and a top speed limited to 155mph (or 186mph as part of the £2760 AMG Driver's Package, which also includes driver training). The S 65 powered by the wholesome 6.0-litre V12 develops a mammoth 621bhp and 737lb ft of torque which helps demolish 0-62mph in 4.3sec.
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, with both models getting the same level of equipment as an AMG Line trimmed S-Class. The S 63 gains 19in alloys, parking sensors, reversing camera, adaptive LED headlights and numerous AMG details, along side the tri-zone climate control and V8 embossed seats.
The S 65 comes with larger alloys, electrically adjustable reclining rear seats, air freshener and V12 embossed seats on top. 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.
Out on the road, one of the impressive aspects of the S 63, 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. 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 577bhp V8.
At speed the S 63 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, 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, choose an E 63 AMG.
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 S 63 AMG wants for nothing, although there is, predictably a myriad pricey options. But it is hard to think of the S 63 AMG in pragmatic terms.
The truth is, if you want to travel in unparalleled comfort and refinement, then a cooking S-Class, 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.
However, the S 63 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.