The CTS Turbo MK3 Scirocco 3" cat-back exhaust system is hand tig welded using the finest T304 stainless steel. Other Scirocco 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 Scirocco cat-back is ideal those of us chasing serious horsepower.