Im trying to figure out which diameter to run. I am currently running with the secodary cats gutted and a custom x pipe but no mufflers. I had a set of borlas but i didnt like them. I am looking at a set of FM single chambers but i am unsure of the diameter. i know that all of them can fit but will running a 3" in/out change the sound at all?? I am going to dump them just before the axle so HELP PLEASE!!!