I've got a 1998 Mustang GT with a Cold Air Intake, Dual Catback Exhaust, 3.73 gears, and a short shifter. The car is also lowered 1.5 inches and I believe it has an aftermarket throttle body but I'm not entirely sure on that one. Currently has about 162,000 on it. What kind of mods should I be looking at doing that would give me some pretty decent power gains that I'm going to feel? I have a budget of about $500 at the moment for whatever I do during this stage. I've been told to chip it, under drive pulleys, and even nitrous. What should I do?