Oh well then, You've got A LOT of possibilities. (I too have the 2.4 and have been on a power hunt since I got it, I've learned a lot)
What I've done is an intake, WAMS 93 octane tune with transmission tune, and a resonator delete on the exhaust, that was only for the sound.
Between the intake and tune the 4cyl feels a lot better!
If you try to run an intake without the tune you may get a check engine light for it running lean. This can be solved with an intake insert that goes by the MAF sensor. I actually just started a thread about it here: https://www.g6ownersclub.com/forum/sh...ad.php?t=13053
But aside from that, there's actually a lot of things available for this motor. As you look for performance parts you're better off searching for a Cobalt SS 2.4l. That's how I found my intake, torque damper, and my future SuperCharger kit.
ZZPerformance.com is a great website for ecotec parts and improvements.
You can go as far as a bolt on SC kit or Turbo kit. Performance Cams. Of course intakes, and such. You can even go as far as building the internals for a few grand and push some serious power, but what's the point in a FWD car right?
If you're looking for a bit more power on a budget, I'd go with the Intake and Tune. That should all be had for a few hundred but it really help, and really makes the engine sound good when you get on it.
WAMS states the tune will add 12-15hp. And I believe it, for a 4 banger my car drives almost like a 6cyl now.
Here's WAMS website for the tunes:WAMS