Which type of c4 are you running? case filled or pan filled? I want to run longtubes (1 3/4) and have read that pan filled can cause problems on "some" vehicles, was seeing if the mustang fell under the "some" category. If you run 1 5/8 please post too, i would rather have some info than none. I dont think there should really be problems considering people run aod's with 1 5/8's but would like peace of mind either way. thanks.