Increased horsepower and torque and improved fuel economy. Reduces back pressure and increases power and efficiency. Improved throttle response and reduced under hood temperature. 409 stainless steel mandrel-bent primary tubes. Premium quality hardware included. 3/8" thick laser-cut single piece flanges. Large 1-5/8" primary tubing. Easy bolt-on installation and will not void factory warranty. C.A.R.B. certified 50 state smog legal. Great horsepower increase. Welding required.