Our header/catalytics for the GT3 is aimed at those who are looking for more torque in the mid range, a rich, deep exhaust growl and most importantly._x000B__x000B_- high durability for track and street use._x000B__x000B_By reducing the back pressure up to 20 (15kw) crank hp and 13 (15NM) crank torque._x000B__x000B_- for cars with OEM side mufflers_x000B_- Manifold with 200 HJS "HF" Tri Metal catalysts