:scratchhead:Hi Oldman how are you doing?.I need some tech advise.Lets take 2 resonators.1)body is 12in, total length is 17in , w/4 in round and inner tube of 2.25. vs 2)body is 16in,total length is 21in,w/3.5 round and inner tube of 2.25.Which has more backpressure and is quieter? Thanks for your expertise