If you're looking for an easy way to improve the sound and mileage of your 2005-07 Dodge Cummins, Aero Performance Products has the answer. The 57D Dodge adapter kit will replace the OEM muffler while keeping your stock 4-inch exhaust system. The patented technology of the Aeroturbine 4040XL muffler will increase fuel mileage 8-12 percent and drop exhaust gas temperatures up to 80 degrees by eliminating the restriction caused by OEM mufflers. For more information please call Aero Performance Products at 877-266-5356 or visit www.aeroexhaust.com.