yes, the M112K engine in the SLK32 is shared by the SRT6. You can install a larger crank pulley onto the engine. Though you do not use the 172/180mm pulley. The most common pully sizes on the M112K are 178, 181, and 185mm. Though the Eurocharged/ASP new design seems to only incorporate the 181/185mm pullies.

The 172 and 180mm pullies are used ono the big brother engine the M113k out of the 55 AMG cars (i.e. E55, CLS55, etc...but not C55)