Magnaflow D-Fit Performance Muffler Replacement Kits replace the restrictive factory muffler, while maintaining the OEM piping & tailpipe. The straight through design muffler reduces backpressure creating more power and increasing diesel fuel economy without replacing the entire exhaust system. Direct Fit muffler kits are one hundred percent 409 stainless steel and made in the U.S.A. The tubing is mandrel bent and the muffler and exhaust tip are mirror finish polished stainless steel. The exhaust tip is an easy to install clamp-on design. Limited Lifetime Manufacturer Warranty.