Hey guys, Ive got a set of Flowmasters in the mail and now Im shopping for new exhaust tips. Ive pretty much decided to go with a Magnaflow tip (unless you guys have any other suggestions). I jus want to know if theres much of a difference between 3, 3.5, and 4 inch pipes, as far as sound goes. Also, should I go with 18 or 22 inch length?? Thanks.