as far as the best route to take.. if you are completely stock. start with an intake and exhaust.. and don't waste your money buying a pre made performance exhaust, go to your local exhaust shop and have them make you a cat back, then get a test pipe to replace your catalytic converter, then go to
www.3sx performance.com and get a performance down pipe, then go to
www.3kgtmotorsports.com and get you a set of headders.. between those 3 sites you should be pretty much set for anything you could possibly want to do to your car. and just for good measure here's another.
www.dnperformance.com
Craig