With the entire Mercedes-Benz lineup to choose from, you’re never quite sure what car official tuner Brabus will choose to display at the Geneva motor show: It could be anything from a Smart Fortwo to a G-wagen.

This year though Brabus will display what it does best: A hugely fast saloon. By applying its PowerXtra B40S performance package to a Mercedes-AMG C63 S, the Bottrop-based concern has liberated 641bhp, a 3.7-second 0-62mph time and a headline 200mph top speed in a car it calls the Brabus 650.

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As Brabus puts it, the best way to extract power from a turbocharged engine – like the 4-litre ‘hot vee’ V8 of the current C63 – is raising boost pressure. While some might stop at that alone, Brabus has developed its own special turbochargers for the car, with a larger compressor unit and stronger internal bearings.

With a new ECU and changes to both injection and ignition, the B40S package lifts power from 503bhp to 641bhp and torque from 516lb ft to 604lb ft, developed between 1750-4500rpm.