Does the brand of the pipes really matter? Is there any performance upgrade between one 3 inch pipe and another? If they are all aluminized, mandrel bent tubes, does the summit kit for 249 work as good as the pypes exhaust for almost double the price. This is just the pipes themselves were talking about, not actuall mufflers. Also, is there any change in performance between shorty headers and full length headers, i originally planned on hooker full length, but now realize i should get shortys, my 70 is going to be 2-3 inches lower all around...Thanx Josh