I have a 2001 gt and all i have done is off road x pipe,cold air intake, and short throw.I am asking for some on to tell me the best bolt ons for these cars with out going internal and if you have any suggestions please tell the brand you prefer thanks
Its going to depend largely on what your goals are and how much money you'll end up throwing at it. You really need to determine your long range plans and then develop a blueprint to get there. It'll the most cost effective way to go.
With that said if power is what you're looking for the most cost effective mod is FI.