I have a used Mac Pro Chamber on road, has catalytic converters, mid pipe for a 99-04 Mustang GT. This pipe may also fit a 96-98 GT with the 4.6 motor. The mid pipe is interchangeable between stock manifolds and shorty headers, as well as long tube headers. These Pro Chambers give a really nice mellow rumble to the 4.6 and scream at higher rpm's. This will give your Mustang a nice little bump in torque and hp along with the improved sound. Any questions please feel free to message me on here or call/text anytime at 7853021716. Thanks for looking!