I'm surprised that GM is using the supercharger, I think that the supercharge phase is over. MB is phasing them out and is joined by Audi and BMW in a "NA-phase" trying to show superiority this way.
Basically anyone can throw a supercharger onto a car and make it go like stink, but it doesn't say much about engineering.
I guess they feel this is what they need to beat the 997GT3 and RS at the 'ring.