Can anyone tell me what is the main difference between the 12, 18 and 33 inch long cherry bomb? Is it just the sound or something else? Also, is it better to have it welded on to my exhaust or is a clamp kit going to do the job? I have 53 Chevy Bel Air with a standard straight 6 engine and single exhaust. As a newbie this is my first question of many! Many thanks and hope you all have a killer weekend!