Most automotive manufacturers offer performance computers that can be purchased and installed fairly easily. Aftermarket, you will see them called a performance chip. Changing your air filter over to a K & N can be done on some vehicles which can help performance as well as fuel economy. Each of these can be done legally, however if your vehicle is covered under a factory warranty any performance parts can void your warranty so be sure to check with your dealer.
〉 Answered on May 6th, 2009 by Karen Davis, Service Manager at Smith Stokes
Probably the easiest thing would be to put a turbo on it. You could also get a cold air intake, you could also replace the exhaust, intake and headers along with a high flow catalytic converter. You can even replace the ECU. It really depends on how much money you want to spend.
Find a high performance shop in your area and go talk to them. From what I hear, they can give you all kinds of advice.
Take a look at this article.
〉 Answered on May 6th, 2009 by Lori Johnson, Owner and Instructor at Ladies Start Your Engines