The B63 uses Mercedes' 5.5 litre V8 Bi-turbo engine and produces, you guessed it, 620bhp. Oh, and 604 lb-ft of torque. 0-62mph is achieved in 5.1 seconds. Top speed is limited to 143mph - amazing for a vehicle with such brick-like proportions.
To create the B63, Brabus take a 'standard' G 63 and add lots of mad stuff like 23 inch wheels (with road tyres), Brabus Dynamic Ride control, the Brabus 620 PowerXtra module (which increases boost pressure and recalibrates the engine mapping), a Brabus stainless steel exhaust which exits on either side of the car just ahead of the rear wheels, and a Brabus bodykit and spoilers.
And, if you're in the mood for some individuality you can specify all sorts of unique interior trims including something called 'yacht design trim'.
Prices haven't yet been announced but expect it to be above £150,000 - and that's before you start to spec your B63. The Mercedes-Benz G 63 AMG costs £118,000.