both. steel with a ceramic lining to keep heat down lighter too. yo the ceramics are steel also and they do rust. any posted hp gains are not definite it varys with each application. i hear dcs,comptechs, and several others are good 4 street use there are some headers best used for serious allmotor power. and if you plan to do an engine swap or turbo any time just forget the header alltogether because it would have to go.

 

okay, so are CARB legal headers less effective then illy ones?

 

no not necessarily its all about the bends and lengths of pipe these effect low end midrange high end etc you follow so your options vary as to just what you want out of a header. shouldnt need to mention this but most of the cheap stuff aint worth the money or time. as far as hp gain its just a general statement most headers add 7 to 12 or like 10 to 15 or so they all say that like intakes give 5 to 10 or expect a 10 hp gain from this so and so exhaust. if you live somewhere wher the law willpull you over and ask you to pop the hood get the one w/carb #