Prototype mules have been caught on several occasions undergoing high-speed testing on Germany's (in)famous Nürburgring circuit. The performance of the new sedan had better be amazing if it expects to compete with the Audi’s RS4 and upcoming RS5 as well as BMW’s next-generation M3. The final output from the V8 engine will be above 450hp, a significant leap over the current C55's 5.4L output.
The car will also pick up a modified version of Mercedes’ new seven-speed automatic transmission, with drive being sent to the rear wheels. An AWD model is also expected further down the track. Coming as standard will be a set of lightweight 18in wheels filled with huge grooved and ventilated discs with six-piston calipers up front. Other key differences will be a set of quad tailpipes and rear diffuser. Expect the new C63 to hit showrooms midway though next year.