If you don't wanna pt too much money into the car then why are you willing to spend up to $4,000? What mods do you have now? For $4,000 you can do a nice h/c/i package and if you do the labor yourself you can put that money towards a tuning device. I recommend trickflow TW heads with an edelbrock RPM intake and an FTI or camshaftinnovations.com cam. I also recommend 1 5/8" longtubes, 30lb injectors and a 75mm TB among the rest of the stuff you'll need. I also recommend 373-410 gears and drag radials.