Mac 2005-07 Mustang GT 2.5" Hi Flow Catted Pro Chamber for MAC Long Tubes. MAC has done it again with the release of the all new ProChamber for the 2005-07 Mustang GT. This particular pipe works with the MAC Long tube headers. This is a 100% simple bolt on for your 2005-07 Mustang GT. Most cars have seen gains up to 20rwhp with this simple bolt on. This pipe not only makes great power, but also sounds amazing! You owe it to your 2005 Mustang to bolt on a MAC Prochamber and make it sound as good as it looks. ** This pipe does have Catalytic Converters although they can actually be removed and replaced with offroad pipes! Check out the picture above. This pipe is great if you live in a state that is big on checking for emissions. In 0 minutes you can switch from Hi flow cats to a true offroad prochamber.