Brabus is a German tuning house that take fast Mercedes AMG cars and makes them even more psychotic.
The latest to pass through their doors is Mercedes S63 AMG. The final result, the Brabus 850 6.0 Biturbo Cabrio, the World's Fastest Four-Seat Convertible.
To help it claim the title, Brabus has taken AMG's mental 5.5-litre twin turbo V8 and has bored it out to 6.0-litres.
The bored out engine produces 838bhp (the S63 has 577bhp) and 1450Nm of torque. The torque has been limited to 1150Nm to ensure it doesn't destroy the drivetrain.
The Brabus 850 can sprint from 0-100km/h in just 3.5 seconds (the S63 AMG takes 4.3 seconds) and has an electronically limited top speed of 350km/h to help save its tyres.
The power and torque are sent to all four wheels through a 7-speed automatic gearbox.
Brabus has fitted quite a few bits made from carbon-fibre including the custom surrounds for the air intakes as well as the aero kit which includes a front splitter, rear spoiler and the diffusor.
Brabus has also added monobloc alloy wheels which are available in sizes ranging from 18-inches to 21-inches.
Inside, the wood and other inserts have been replaced with carbon-fibre while the paddle shifters are made from aluminium.
The Brabus 850 is currently on sale as a complete new car though owner of the S63 AMG can get theirs made into a mad Brabus 850 by handing theirs over to the madcap tuners.