Rumor has it Mercedes is preparing to go after the BMW M3 Coupe with a coupe of their own. The C class coupe would share the drivetrain from the C63 sedan which would mean it would get the same 6.2 liter V8. If Mercedes shoved their new twin turbo V8 in this thing, they would instantly dominate the landscape but most likely be stepping on the toes of their more expensive AMG models which is why they won't do it.
This car is obviously aimed at the M3 and will clearly outmuscle it along with the RS5 which doesn't really have much muscle. The CTS-V coupe clearly would also be one of the targets. The car will not have a dual clutch transmission unfortunately which is a bit of set back. Note, much of this information comes from Autocar so don't take this as confirmation of a specs just yet, things may change.