The only thing I've done is put in a K&N drop in air filter. Just recently I did the Wolf Bumper Mod to my car. Though I tried to mix up a batch of paint myself to fill in the holes left in by the bumpers, but it didn't match up. I'm hoping the pebbles that hit the bumper will make it blend in.
www.geocities.com/dvl999/page44.html
-Gus.