Well basically, intake and exhaust. After that, it kinda gets expencive...turbos need replacement if you want more than 14 psi, I think you need a standalone/piggyback as well, alllll sorts of stuff. Thats all I can think of off the top of my head...I havent looked into 1JZs since I last gave up on them for not having the money to get one...

Andy and Psifactor could tell you plenty, they actually have/had a 1JZ. Once Kyle starts coming to the meets, he can ask Andy himself

www.1jz-gte.us comes to mind though