The Banks Monster Exhaust is engineered using computational fluid dynamics (CFD) software then tested on both dyno and on-road. Reducing backpressure allows the engine to expel spent gasses with less effort. Less pumping loss means more horsepower, lower EGTs, and improved fuel economy. The Monster Exhaust system cools while flowing up to 80% better than stock! Cooling without killing flow is a major challenge. But the Monster Exhaust wins on both counts thanks to its mandrel-bent constant-diameter tubing and huge Ob-Round patented SideKick tip. The tip is the key. Its unique shape mixes hot exhaust gas with cool ambient air. And, it keeps your trailer safe by directing exhaust gasses to the side. Ob-Round SideKick tip directs hot exhaust gas away 4-inch mandrel bent Stainless Steel construction Dramatically improves flow up to 80% Slashes backpressure by nearly 57% Lowers exhaust gas temps Huge polished CHROME tip Maximum Airflow Emissions Compliant: E.O. Not Required US Patent #5,581,111 S1