Re: Cheap Performance Mods
You should consider upgrading the following
You can replace the cats with high flow Magnaflow cats, and a free flow muffler of your preference. My recommended exhaust tubing size is 2 1/4" where dual and 2 1/2" or 3" if single. It is cheaper to maintain the stock exhaust routing with upgraded cats, muffler, and tubing diameters rather than making it dual. Dual exhaust adds more weight to the vehicle and more weight makes you slower. Performance won't suffer with a single exhaust.
You can spend 200 or more bucks on a KandN intake, or you can make your own with PVC tubing or at the muffler shop. Use your imagination! PepBoys sells Mass Airflow meter adapters and conical air filters, and if you are creative enough you can install the aftermarket air filter in the OEM air box(it ensures colder denser air.) That way you improve air flow the same way the KN kit does for much less.
Gearing is all about sacrifice here gain there kind of thing. If you change your 2.73 for umm... 3.73 you gain acceleration but loose top speed, and since these cars have plenty of top speed...
Your car is now ready for other upgrades. Like, pistons, camshafts, an ecu, nitrous, etc.