I am looking for performance upgrades for my 2007 Cobalt LS w/ 2.2L. I don't have a lot of experience with 4 cylinders other than VW's and those are a different animal, as they say. I have already done a K&N Typhoon cold air intake system. I don't care how expensive an upgrade is - I am looking for performance, first and foremost. I don't have a lot of time for research, that is why I am asking.

I would like to start with an exhaust system but I don't want my vehicle to sound like all the wannabe street racers out there. I have looked at the Corsa and the Borla systems. Any input on the sound and performance from those systems?

I have read about the intake manifold upgrade from Crate Engine Depot, but have heard they are not filling orders. Has anyone ordered this and received it? How was the performance gain? Has anyone done a 2.4L intake swap? Did you do this and the injectors from the 2.4L? Did you re-tune after?

Any throttle body spacers available? Any Power Programmers available?

I have also seen a turbo kit on Summit Racing Equipment's website. Has anyone done this upgrade?

Any info/feedback would be appreciated. Thanks for your time in advance.

I forgot to mention that the vehicle must retain it's stock appearance.