12% more flow than a single muffler system. The Streetster Dual Quiet Pack is the ultimate in high performance exhausts for VW Sedans, Buses, and Ghias. The rotation firing order, and smooth interior of the header pipes result in spiral movement of exhaust gases into the "short merge" collector. Your engine will run cooler and develop more usable power due to the improved flow of gases. The Streetster Dual Pack will improve the efficiency of all engines from a mild 1200 to big bore strokes. The headers are shipped with gaskets and mounting hardware.