The days of Mercedes model naming giving any indication as to what's under the bonnet are long gone. The Mercedes E63 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 has sprouted a pair of turbochargers. It is the same V8 mill already found in the CLS63, S63 and CL63 AMG.
In standard guise, the blown unit kicks out 517bhp, or the same as the old engine, although peak power is now developed 1550rpm earlier in the rev range at 5250rpm. Torque has risen by over 11 per cent, jumping from an already potent 464lb ft to 516lb ft at just 1700rpm, or 3500rpm earlier than before.Place a tick in the box marked Performance Package and AMG provides the new E63 AMG with an upgraded engine management system. It introduces an additional 0.3bar of turbocharger boost pressure among other measures in a move that raises output to 549bhp at same 5250rpm, while raising torque a further 74lb ft to 590lb ft at 2000rpm.
The performance of the new turbocharged engine is clearly more accessible than that of the old naturally aspirated unit, which needed to be worked harder before delivering its best. The defining characteristic is the enormous flexibility that is created as the two turbochargers.
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 E63’s new engine, you need to call up Sport Plus. 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.
Mercedes-Benz claims the standard E63 saloon, which weighs the same as is predecessor at 1765kg, hits 62mph from standstill in 4.3sec, or an even sharper 4.2sec when optioned up with the Performance Package, making it a respective 0.2secs and 0.3sec faster up the strip than the old model, whose engine was available in just a single state of tune.
Top speed, like all AMG models, is limited to 155mph, although the Driver’s Package option, which also gets the buyer a day of high speed driver training, bumps it up to a limited 186mph.
Given the heroic performance, the new E63 is reasonably economical, too. Official figures suggest it’ll return 28.8mpg on a mixture of city and motorway driving for an improvement of 4.5mpg over the old E63. In the real world, though, the figure is closer to 24mpg. Go for broke and it quickly dips below 20mpg.
The E63 is capable of shaving ten seconds off the old model's lap time at the Nurburgring, bringing it under eight minutes for the first time. Not too shabby for a car that car carry five adults and nominal 540-litres of luggage in saloon guise, rising to 695-litres for the estate.
With all the regulatory measures in place today, it is becoming hard to justify owning a car like this in Britain. However, those in the market for a rapid four door saloon or estate will no doubt be tempted by the Mercedes-Benz E63.
The changes AMG has brought to its latest model make it a better everyday proposition while extending its already haughty performance potential and providing it with impressive fuel economy when driven at posted limits.
It's not cheap, of course, but 500-odd-bhp supersaloons rarely are. Its price matches that of the BMW M5, but the Jaguar XFR - a model which in our eyes edges the Merc - is around £10,000 less.