Our high flow performance exhaust systems maximize exhaust flow so your engine keeps its cool with lower exhaust temperatures. Your reward will be greater fuel efficiency; more torque; more horsepower; and last but not least a sound that is pure MBRP. Pro Series Cat Back Exhaust System; 3 in.; Dual Split Rear; 4.5 in. OD Tips; T304 Stainless Steel; 4.5in. Outside Diameter Tips Included.