The CTS Turbo MK6 Gen 3 GLI 3" cat-back exhaust system is hand tig welded using the finest T304 stainless steel. Other MK6 Gen 3 GLI exhausts that are currently available can choke peak power and limit the breathing due to their 2.5" construction. The 3" design of the CTS Turbo MK6 Gen 3 GLI cat-back is ideal those of us chasing serious horsepower.