cai - waste of money. after having a k&n cai and custom tunes and going to the gotts mod with custom tunes, the gotts was a much better alternative and for only like $10. my cai had wayyyy too much drone and seemed to not give me any results. exhaust - i cut off my stock exhaust just in front of the muffler and put on a dynomax bullet, $40 btw, and had it exit in front of the rear tire. sounds real deep and loud, similar to a glasspack but no snap, crackle or pop