I am asking a question for a friend. He has a stock GTP and wants to run a 3.4" pulley. What exact mods would he need to support this. I just want to make sure I am telling him the right stuff. Cold air intake, catback exhaust, PCM, colder plugs and thermostat. Do I have it right or am I missing anything? Don't want to see him end up with alot of KR. Tryin g to remember everything I did. It's been awhile.