DNA Motoring CBE-NM04V6-D-NRT CBENM04V6DNRT Stainless Steel Catback Exhaust System Made of high quality T-304 Stainless Steel with computerized mandrel-bends for strength and durability TIG welded CNC machine flange for resistance against pressure and corrosion Aggressive deep and smooth tone sound while ensures smooth exhaust gas flow Dyno proven to instantly increase 15 to 25 horsepower or low end torque 4"(Od) dual Muffler rolled tip/ 2. 25"(Id) inlet/ 2. 25"(Id) main piping/ 14mm thick double walled Muffler tip Color: Chrome Surface Finish: Polished Muffler &amp; Tip / Bare Piping Inlet / Outlet Diameter: 2.25&#034; ID / 2.25&#034; ID Tip Diameter (IN): 4&#034; OD Tip Type: Round Double Walled Rolled Tips 04-08 Nissan Maxima Made of High Quality T-304 Stainless Steel with Computerized Mandrel-Bends for Strength and Durability Gaskets and Hardware Included Notes: Installation instruction is not included. Professional installer is highly recommended There are a few benefits that come from using an exhaust cat back system, such as increased horsepower and fuel efficiency, as well as, an aggressive sound and stunning aesthetic. But to fully grasp these benefits we first must understand the engines combustion cycle. Increase in horsepower, torque, and MPG Louder, more aggressive tone Stylish appearance Quality Materials Our professional technicians do heavy research and development in testing car applications and fitments for our products. We also do rigorous testing on the strength, durability, as well as longevity of the material in order to make sure when the product arrives at the consumers end that its ready to go without worries.