S2000 isn't in the same class as the Cobalt SS/SRT-4. The Civic Si is in their class because they are basically the highest/sportiest model of their specific car type.

You can't compare a 2-seater, RWD, convertible that is overpriced at $35k to cars that sell for under $25k and are FWD sporty models aimed at the younger crowd.

For the segment I say the Mazdaspeed is the best buy simply because its actually a REALLY nice car for what you pay IMO. I've driven all but the turbocharged Cobalt and I have to say it was the most comfortable and quickest out the cars stock feeling to me.

Mazdaspeed3 > SRT-4 > Civic Si > Cobalt SS until I see new power numbers from the Cobalt thats how it will stay for me cause the supercharged ones didn't impress me much.