I don't have a lot of automotive knowledge but I know Cobalts so I will chime in here...
Only problem with the 05-07s is with the stock cat, which is covered for replacement even if you are out of warranty, and a power steering motor recall which doesn't effect all of them. With light mods they can be at 260+ hp to the wheels easily.
The stock turbo model clocked the fastest FWD time at Nuhrenberg (sp?). GM has a stage 1 kit that puts the car at about 290whp/300wtq that keeps the 100k drive-train warranty intact. (The turbo model also has a different direct injection LNF engine as opposed the supercharged LSJ.)
The big "issue" (aside from lack of street cred, LOL) with them is they have pretty much had the same interior/exterior since '05. That, coupled with the torque steer, and I would say you would be much happier with most of the other cars you are considering.