J2 Engineering For Stainless Steel 4" Rolled Tip Catback Exhaust Muffler (Left) for FRS/BRZ 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 OEM Muffler 26 lbs. Muffler Delete Axle Back is Only 3 lbs. Massive Weight Reduction of 23 lbs. Increase Engine Output and Efficiency / Dyno Proven to Instantly Increase 15 to 25 Horsepower and Low End Torque Double Walled Muffler Tip / 2.25" Inlet / 4" Outlet (Driver Side ONLY)