what is the big diffrence between the 2? For dual you have to get 2-1/2 inch exaust then a 3 inch tip. Single you would use a 3 in exaust and mabey a 3.5 in tip. I read allot of people running dual. is there any body using a single. What about removing the cats and a single exaust out to the side. Its for a 5.4 supercab. thanks.