I just joined mustangevolution.com and am also interested in mods for '07 Shelby Gt. This thread has been very informative for me as well. Instead of posting a new thread with the question I have, I thought about just adding into this. Recently both my exhaust pipes were damaged and I am looking into what type of exhaust to get? I have been browsing through STRAIGHT THROUGH / RESONATOR MUFFLER AXLE-BACKS and CHAMBERED MUFFLER AXLE-BACKS. Do you know what the make and size of the original exhausts are on '07? Any help would be most appreciated!!