Early reports had indicated that a C63 version would use the 6.2-liter V8 that Mercedes is currently decommissioning, but that seems unlikely. Instead, it should get the new twin-turbo 4.7-liter that makes 435-hp. As for the Black Series model, it will come with the new twin-turbo 5.5-liter V8 that makes as much as 563-hp.
InsideLine reports that the vehicle was confirmed by an unnamed Mercedes exec, who described it as an M3 killer.
[Source: InsideLine on Twitter]