Im not running the RB pre silencer... lol.... otherwise i would be selling it as well. My setup right now consists of the RB header (ceramic coated) vband clamped to a 2.5 inch pipe, run into an expansion chamber (2.5 - 3.5 - back to 2.5) out to an RB muffler.... No cats.... no pre silencer.... and quite a few of you have heard it... its not very loud... Picked up 10hp over stock after putting it on...