Improves airflow up to 72 Percent. Nearly doubles flow. 4 - inch constant - diameter downpipe - back system with Straight - through muffler. Easy install. Tip optional. Compatible with factory warranty. Monster Performance Modest Price. Banks' new Monster Sport Exhaust for your 7.3L Power Stroke F - 250 and F - 350 is one cool system And its low price That's way cool. The system slashes backpressure, increases exhaust flow, improves fuel economy and delivers extra power to your rear wheels. Exhaust tip optional. Important Some vehicle configurations require an extension kit for proper fit. 4 inch constant - diameter exhaust system. Virtually eliminates backpressure nearly doubles the flow Lowers exhaust gas temps. Straight - through Monster Muffler delivers a commanding exhaust note. 100 Stainless Steel. Easy install. 5 inch rolled - edge polished tip is optional. Fully compatible with the Ford factory warranty. 5 - Year Limited Warranty. Extended Cab Long Bed kit 53517, Crew Cab Short Bed Kit 53516 and Crew Cab Long Bed Kit 53518