The new Cobalt SS is crazy fast through the twisties…it had the FWD record at the ring. It is designed to handle badass, where the G8 is designed to be a good handling 4 door sedan. Maybe a GXP could hang with the Cobalt but not a GT. Stock 1/4 mile dudes on the G8 board are running 13.5’s so that is sweet and one guy with the tune and intake ripped off a 12.9.
One thing is I would want to keep the warranty, so I think the tune may void it.