I realy dont know if i can help you or not,maybe i need help?I have an 07 and put the 18'' magnaflow muffler swap on.After putting the Stillen Headers on i find my self putting the JBA cat back exhaust on.I'm trying to get all the power i can out of this truck and maybe be one of the first to go sub 13 in the 1/4 mile being N/A. Good luck to you.