Headers
 

I own a 99 with tip.I have a chance to buy a set of used headers from a part out car.My car has a CAI and a smaller under pulley. I`m looking for some more HP.Can I install these without deleting the cats? What changes have to be made electronically ? Is this a remove and replace thing or a lot more ? I`d like to stay away from replacing the whole exhaust,

You'll be fine. The headers can run without any other changes, some people do have check engines lights turn on afterwards though some don't.