Well i have figured out my first goal is to shut up a co-worker of mine with a stock g35! He thinks he has the absolute king of all cars and well I'm getting sick of hearing about it. I guess I'm going to start with the basics, intake, pulleys, and a full exhaust (not just cat back). Also if anyone has any personal info about the cat backs i would like to get some info about the diff. brands. I have heard most cat backs just change the tone for the most part? and you don't see to much power gain?