I'd redo the exhaust (dual exhaust, Y-pipe, but do not remove the resonator!!!) Bigger throttle body, new air intake (K&N). Then get some custom wheels and exhaust. Maybe a speed chip, and if you want interior mods, the A-pillar guage pod. Get a nice stereo system, and perhaps better brakes and suspension components. Anything else and you're wasting $$. That can all be done with $3500..
Nate