How does 634 horsepower and 608 lb-ft of torque at the wheels sound? On pump fuel no less? No methanol, no E85, just what you can easily run every day.
The other modifications are downpipes and an aftermarket exhaust. That's it.
Considering the heft of the C63 the added torque will be appreciated. Plus, F80 M3's are showing strongly so an M177 turbo upgrade is a good idea for W205 C63 owners who want to easily dispatch tuned competition.
As for the M178 under the hood of the AMG GT, results for that will have to wait for now until someone does the upgrade.