I recently purchased a 2003 mustang cobra with a few mods, and would like to upgrade the exhaust. The car pulled 480rwhp and 470rwtq. it currently has a mac o/r h pipe and a 2.5" mac catback. I do need cats for i live in vermont and need them for our state inspection. There are 2 exhaust combinations i have been thinking of getting. Either Kooks 1 3/4" long tube headers with a kooks 3" catted X pipe, with a Mac 3" catback. Or SLP 1 3/4" long tubes headers with an SLP 2.5" catted X pipe, and a Mac 3" catback. i am not sure if i would lose torque from the 3" x pipe because of the decrease in back pressure. I am trying to get the most performance that i can out of an exhaust combo so if any of you mustang experts out there could give me some advice on my issue it would be greatly appreciated.
-James
-James