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 #