With added turbocharger boost pressure, the downsized AMG engine endows the new C63 S with an even more potent 503bhp at the same 5500rpm, along with 516lb ft from 1750 to 6250rpm, giving it 23bhp and 74lb ft more than the old C63 equipped with the optional Performance Package. It is also more than the previous limited volume C63 Edition 507, which had 500bhp and 450lb ft.
By comparison, its keenest four-door performance rival, the newly introduced fifth-generation BMW M3, offers 425bhp at 5500rpm and 405lb ft from its twin-turbocharged 3.0-litre six-cylinder petrol engine. Among the five-door estate competition is the Audi RS4 Avant, whose naturally aspirated 4.2-litre V8 delivers 444bhp and 317lb ft.
With a kerb weight some 15kg below that of its predecessor at 1640kg in saloon guise, the new C63’s power-to-weight ratio has risen by 14bhp per tonne over its direct predecessor to 286bhp per tonne.
The C63 S saloon tips the scales at the same kerb weight as the old model, at 1655kg, giving it an even sharper 304bhp per tonne, or 14bhp more than the car it replaces.
Channelling the sturdy reserves to the rear wheels is an updated version of AMG’s seven-speed Speedshift MCT automatic gearbox.
Combined with remote steering wheel-mounted aluminium shift paddles, it offers the driver the choice of up to five different modes via a so-called AMG Dynamic Select programme: C (controlled efficiency), S (sport), S+ (sport plus) and, exclusively in the C63 S, R (race).
An additional manual mode can be accessed via the shift paddles, although the gearbox is programmed to revert back to full automatic operation for improved fuel economy savings.
AMG’s official performance claims reveal that the C63 saloon has taken a significant step forward in terms of straight-line speed with a 0-62mph time that undercuts its predecessor by 0.4sec, at just 4.1sec – the same figure BMW quotes for its latest M3 in automatic form.
In estate guise the new C63 hits the traditional acceleration benchmark in a claimed 4.2sec – some 0.5sec inside the time Audi claims for the RS4 Avant. The C63 S is marginally quicker, with respective times of 4.0sec and 4.1sec for the saloon and estate. The top speed for all models is limited to 155mph.
Despite early rumours suggesting that AMG would follow the example of the latest E63 and S63 by providing the new C63 with optional 4Matic four-wheel drive, it is not available on the launch models.
As well as establishing lofty new performance benchmarks, the new C63 also boasts class-leading economy, according to Mercedes-Benz’s official claims. Combined cycle fuel consumption has improved by 11.0mpg over the outgoing model to 34.5mpg, allied to average CO2 emissions of 192g/km. The C63 S is marginally thirstier with figures of 33.6mpg and 195g/km.
The C63 rides on a heavily upgraded version of the standard C-class suspension, complete with three-stage adaptive damping as part of AMG’s Sport Ride Control system.
Among the detail changes over its standard sibling is a wider front track, unique rear wheel bearings offering greater negative camber for improved traction, firmer springs and dampers, altered bushing and a 25mm reduction in ride height.
In a move mirroring that of the GT, the standard C63 receives a mechanical locking differential, while the C63 S gets a more responsive electronically controlled locking differential.