Megan Racing Resonators and Test Pipes offer the ultimate in high-flow performance. Offering substantial horsepower gains in the higher-end of the power band, the Megan Racing Test-Pipes are made of Stainless Steel with a quality polished finish. The Megan Racing Universal Resonators are also made of Stainless Steel and a straight through design, but serve to give your custom exhaust system a more mellow-deep tone while catering to traffic laws and regulations. (Note: The test-pipe is for off-road use only and is not intended for highway use. O2 Simulators may be required if a CEL is triggered.)