Let me just say this: When a chevy car is released, and it comes out with an SS badge, you can bet it'll be fast. Chevy isn't like other manufacturers who put on performance badging for looks alone, they are especially anal about the SS emblems. If it's badged as an SS, you can bet your ass that the car has a major performance boost beyond that of the other trim levels.
If it's badged as an SS from the factory, GM means buisness. You shouldn't feel embarrassed if you get your ass handed to you by an SS, it's a simple fact of life that it'll be a performance car. When GM adds that SS to a car, they are not screwing around. there's always a powerplant in the engine bay to back it up.
Look at some of the other cars GM made with an SS option available.
El Camino SS
Camaro SS (especially the last version)
Monte Carlo SS
All of these cars dominated and set performance trends that other manufacturers had to play catch-up to. The cobalt SS is just GM's way of saying "hello" to the performance compact segment. Note that the high-performance cavalier variant was called the Z24, and some models were actually pretty quick, but, although there were some fakes out there with decals and body kits sporting "SS" decals, chevy never actually made a cavalier SS. Cobalt SS will be the real deal for sure.
BTW, I think the cobalt SS looks better than the Scion TC, very similar body lines, but overall, I think the Cobalt looks better