Also it's going to vary dealer to dealer. Some dealers are complete a-holes, and other dealers can be really good about it.
I really don't know what's going to be available for launch, but if I wanted to get the most power that I could from the exhaust I wouldn't just get the cat-back. If anything it'll give you better sound. You need long tubes, headers, high flow cat. Just not sure if that will be out right away.
Currently Driving: 2006 Cobalt SS Supercharged