Bring the legendary Kooks sound back to your 2015-2017 Mustang GT Convertible with a Kooks Cat Back Exhaust. Not only will you increase sound quality, but you will also notice a huge increase in horsepower and torque. Kooks Cat Back Exhaust system is made of mandrel bent stainless steel with 4″ dia. Slash Cut Tips and 100% polished mufflers.