I am going to get both, but which should I get first. I really don't know! Headers will give a 10 to 15 hp or so, which is pretty good(some people got 20!), and it will sound amazing!

Wheels on the other hand, will make the car have better grip(wider wheels), they will loose a bit of unsprung weight(about 1.3lbs per corner) and they look hella sexy. HELLA!!!!!