Depends on who you talk to and what you want heres is what I got and I love it.I have an 01 GTS here are my mods Injen Cold Air Intake
, Kazuma Exhaust, Trial Headers, AEM
Puleys, Fidanza Flywheel, TRD
or ACT street Clutch, Ground Wires, LSD, Jet Chip. In that order. Clutch, Flywheel and Lsd Try to do all at once. **** Kazuma Exhaust is very very very loud if you live in quite neighborhood don't get it. I have an ApexiN1 exhaust had to sell Kazuma to loud to drive around in especially when you hit lift.