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The one thing the Mercedes E 63 AMG doesn't need is more torque, but that's precisely what German tuning madhouse Brabus has given it, resulting in the epic 850 6.0 Biturbo.

Exterior

As Brabii (that's the plural for Brabus, right?) go, this is fairly restrained. You might spot the massive 'B' in the grille where the three-pointed star would usually reside, but de-badge it and it could perhaps be mistaken for a 'normal' E 63 AMG. Carbon fibre body parts have been aerodynamically honed by the Bottrop bunch to reduce negative lift, such as the front lip spoiler, plus the rear spoiler and diffuser.

The 850 6.0 Biturbo breathes out through meaty quad exhausts and the car sits on Brabus Monoblock R 'Platinum Edition' forged 20-inch alloys, wearing special high-performance tyres.

Interior

There's a handcrafted fine leather interior in here, and you can have it in any colour you like. Further detailing is provided by the Brabus aluminium shift paddles and Brabus Race pedals.

Mechanicals

In order to outdo some of its phenomenal back catalogue - including the 6.9 V12 and E V12 brutes - Brabus has, er... dropped the cylinder count. That's right, as it is based on the 5.5-litre E 63 model, it has a V8 engine under the bonnet. But don't panic, as it has been thoroughly reworked. Forged pistons and stronger rods, optimised cylinder heads, an increase in bore, bigger turbos and a special manifold make this so much more than just a larger lump. The net result is 6.0 litres (it's actually 5,912cc but we'll let Brabus off, seeing as Merc itself has been using '63' badging on 6.2s and 5.5s) of unfettered lunacy that makes a frightening 850hp at 5,400rpm coupled to a scandalous 1,450Nm from 2,500- to 4,500rpm.
So corrupting-ly powerful is it that once it is mounted in the car, it has to be de-tuned to 'just' 1,150Nm to try and preserve the poor drivetrain; Brabus does, however, offer a 60,000-mile, three-year warranty.

Nevertheless, even with 1,150Nm, this mammoth muscle allows the seven-speed auto 850 to punch beyond 217mph while despatching 62mph from rest in 3.7 seconds. Order this as a 4Matic all-wheel drive car and that time tumbles to 3.1 seconds. Brabus is being coy about exactly what it could do but as the E V12 'one of ten' models could apparently hit 230mph with just 800hp at their disposal, the 850 could be the quickest yet. Perhaps most crucially, Brabus says its high-performance exhaust provides an 'earthy, full-blooded V8 sound' when Sport mode is engaged.

Anything else?

Brabus claims this behemoth can return 35.7mpg on the motorway and 27.4mpg combined. Good luck with that. Emissions, by the way, are said to be a reasonably modest 242g/km.

You can either order this as a complete car or convert an existing E 63 AMG to 850 6.0 Biturbo spec. Feeling a little yellow? Then go for the 620-, 650- or 730hp models that Brabus also offers, if you must. Don't like the idea of a stupidly fast saloon but you do want 850hp? Not to fear - Brabus will also offer you this drivetrain in estate format.

Matt Robinson - 16 May 2014