Getting ready to order an exhaust. I am partial to a dual kit like I had on my last truck for the look and uniqueness. Looks like Flo-Pro is the only company that offers a full dp back kit and it is listed as 4" pipe. Anyone know if it is 4" the whole way or 5" before splitting into dual 4"? From reading comments on this site I believe I would like the sound of a 5" better than a 4", but am not sure how the dual outlets affect the sound. Has anyone heard duals and can compare them to a single 4" and 5"? Thanks.