I say cheapo stuff that catches a buyer's eye.. header, intake, catback, springs n struts, tune. That way A) you're still modding on stuff that is cake for you to do, and you more than likely won't run into any problems, and B) You can feel like you're getting more out of the car instead of wasting its potential..keep it N/A with bolt-ons so it sounds mean and performs a bit better.. minimal cosmetic mods, maybe paint, tails, cheap HIDs and light rims.. do some work on the brakes and rotors.. maybe an aftermarket pulley.. SAFC for a tune and for potential buyers to think it's faster than it is :P And then just keep it CLEAN 24/7!