If performance is an important factor for you, then I'd recommend getting an SS.
For its class the V6 Camaro is going to be plenty competitive, however if it means waiting an extra 6 months to save up for an SS, it'll all be worth the wait in the end, trust me.
Most of the people that are planning to purchase a V6 Camaro aren't getting it for the performance, they are getting it for the affordability, and just for the pleasure of having a decent performing and somewhat fuel efficient vehicle (of course not all)
but.... I can say this for sure. You'll be happier with a V8, and you don't want to regret your decision afterward thinking I should have gotten a V8, later down the road...