Brabus guarantees performance with its latest hot Mercedes

The Brabus 650 Cabrio. (Brabus De)

The Brabus 650 Cabrio will offer all of the refinement of an executive German cabriolet but with all the power and ferocity of a super-reliable supercar when it is officially revealed in Geneva.

This is what German tuning firm Brabus would describe as its approach to 'blue sky thinking': taking an otherwise reasonable Mercedes compact convertible and endowing it with 650hp and a 200 mph top speed.

But in order to create the new car, destined for a real-world reveal in Geneva next week, Brabus hasn't simply strapped two huge turbos to the Mercedes' existing engine to boost power (even though the turbos are new). Like all creations based on a Mercedes host, the company has gone through the vehicle with a fine-tooth comb looking at ways to turn the performance up to 11 without in any way compromising the car's integrity or reliability.

As well as upgraded stronger turbos, complete with better cooling and reinforced bearings, the car's been given new exhausts, a reprogrammed engine management chip, and has been subjected to hours in the wind tunnel in order to get the external aerodynamic upgrades just right.

None of the exterior carbon elements -- from the front spoiler to the rear diffuser -- are there for decorative effect. Rather they ensure that the significant power upgrade -- the standard car is capable of hitting 155 mph and accelerating from 0-100 km/h in 4.1 seconds -- doesn't result in the car taking off like a jet plane.

Instead, these elements, plus the lightweight forged 20-inch wheels and uprated suspension setup, should ensure it stays stuck to the road, even at higher speeds.

But of course, most impressively, like all Brabus-tuned Mercedes-Benz cars, when the new 650 Cabrio goes on sale, despite its mind-bending performance data -- as well as 650hp it offers a 0-100km/h time of 3.7 seconds and 680Nm of torque -- it will come with a three-year, 100,000km warranty as standard.

The Brabus 650 Cabrio is just one of five new Mercedes-derived models the company will be bringing to this year's Geneva motor show, which opens its doors to the public on March 9.