Contrary to what you may expect, the Mercedes-Benz E 63 AMG never had a 6.3-litre engine – the old car packed a naturally aspirated 6.2-litre V8. Now the powerplant has shrunk to 5.5 litres but sprouted a pair of turbochargers. It is the same V8 mill already found in the CLS 63, S 63 and CL 63 AMG.
In standard guise, the blown unit develops 549bhp. Torque has risen by a healthy margin though, jumping from a 464lb ft in the old atmospheric engine to 530lb ft at just 1700rpm, or 3500rpm earlier than before.
As part of the 2013 facelift of the E-Class, Mercedes has dropped the old Performance Package option and provides instead the new E 63 AMG 'S' version, with upgraded engine management and intake systems.
It introduces an additional 0.3bar of turbocharger boost pressure, among other measures, in a move that raises output to 577bhp at 5250rpm, while raising torque to 590lb ft. Emissions from the Mercedes remain unaffected.
During the same model-year changes, revisions were made to the E 63's suspension and steering systems, which supply added grip, directness and feedback for the car. This is still a big Benz with air suspension in the mix, and so it does comfort more than well enough. But now it also does involvement and feel as well as any fast four-door.
The car's handling still isn't as naturally sweet or precise as a Jaguar XFR's beyond the limit of grip, but it is hugely enjoyable and, it almost goes without saying, endlessly driftable. And there's a glittering surplus of old-school hotrod character here. There aren't many new-breed executive saloons – with electromechanical power steering and state-of-the-art stability controls – that communicate so honestly and so vividly.
The performance of the new turbocharged engine is clearly more accessible than that of the old naturally aspirated unit, which needed to be stoked up before delivering its best. The defining characteristic is the enormous flexibility that is created, which reminds you of the way AMG's old supercharged '55' engines came on song. At pretty much any revs, in any gear, there is vast thrust. Speed builds quickly and, owing to the smoothness of the delivery, rather deceptively.
To experience the full force of the E 63’s new engine, you need to call up 'Sport Plus' mode. Do so and you discover the reworked gearbox picks off gears with greater speed and precision than before thanks to improvements in the mechanical clutch and changes to the Speedshift software package controlling it.