Hello ppl, found a good used header system for my Si. Need to know if I can use them with my stock exhaust system? I don't have the money for the exhaust for now. The headers are 120$ - sounds ok or can I get them cheaper somewhere else (used)? Also, these work best at higher rmps right?

Here is the pic --> http://i22.photobucket.com/albums/b3...d/DSC00321.jpg