[AlbinoMonkeyRat]

^ Whoever did that to you is a fartknocker

For appearance, go with this order:
drop it ($200-300 on springs, depending on your brand; or up to $4500 if you get juice)
tint it ($100 or so depending on the shop)
exhaust (SLP for dual, Borla for single w/ double tip, not sure on those prices, but the most I've heard is around $400)
and wheels. Wheels can be really cheap if you shop well, or can be 2 months pay if you don't (if you have a part-time job...)

If you're going for performance, there's SO much more you can do, and it would all be a matter of whether you want HP for the strip, or handling for the course. If you want both, start with the handling stuff.