German tuner Brabus is planning to celebrate its 30th anniversary at the Frankfurt motor show in September by unveiling a new model. All it's saying at the moment is that the car will be a "wolf in sheep's clothing".Brabus was founded by Bodo Buschmann in 1977. It started building special models in 1984, when a V8 was slotted under the bonnet of a Mercedes 190. Since then, the firm has gained a reputation for making fearsomely fast modified Mercedes, including the CLS-based V12-powered Rocket, which is officially the fastest street-legal saloon in the world, at 227.2mph.The new car is rumoured to be a stealthy version of the new Mercedes C-class, with something seriously powerful under the bonnet. It'll need to have more than 457bhp if it's to beat the 6.2-litre V8 of Merc's own C63 AMG.