Brabus, world famous for tuning big-engined Mercedes as well as the odd Smart Car, has turned its attention to the new E63 AMG estate. Already one of the fastest estate cars on the market, its V8 engine has had the wick turned up considerably, now producing 838bhp and 848lb ft of torque.

Performance is noticeably improved, with 0-62mph coming up in 3.1secs. But, the biggest difference is top speed, which sees the 155mph limiter lifted to 186mph for the estate. When fitted with high-speed tyres, Brabus says the saloon version can hit a de-restricted 217mph.

It’s the most powerful engine Brabus has ever produced, and the company has gone all out to make it a rather special one. The 5.5-litre V8 has been bored out to 5.9-litres, with a host of new forged internals and a custom billet crankshaft. A pair of optimized turbochargers, and new manifolds complete the package. Brabus claims that it has had to electronically limit peak torque, from the engine’s natural 1,069 lb-ft, to extend engine life.

The Brabus 850 package is available on both four- and rear-wheel drive E63s, and has been shown at the tuner-oriented Essen motor show. There is a Brabus bodykit too, including a front splitter, as well as a rear diffuser with integrated tail pipes. The car can be specified with forged 19 or 20-inch wheels.