Technical Specifications Tips: Dual Round Rolled Angle-Cut Long This system was designed specifically for the BMW 3.0L Inline-6. The system features the mellow Touring sound level and 3.19" polished T-304 stainless steel tips.  Increased exhaust velocity adds power, driving excitement, fuel economy, and the distinctive BORLA® Sound of Power respected by motoring enthusiasts everywhere. Each system is built from premium T-304 stainless steel, superior to T-400 series knockoffs (such as 409), to give you the absolute best in performance and durability. Ultra-smooth mandrel bends ensure maximum flow & power, and precision computer numerical control (CNC) manufacturing ensures an accurate fit. Pipe Diameter Tip Size Tip Exit 2.25", 2.5" 3.19 Dual Left Rear Exit   Fitment 2006 BMW E90/ E91 325i/ 325xi 3.0L 6 Cyl. Automatic/ Manual Transmission Rear Wheel & All Wheel Drive 4 Door/ 2007-2011 BMW E90, E91 328i/328xi 3.0L 6 Cyl. Automatic/ Manual Transmission Rear Wheel & All Wheel Drive 4 Door. Installation https://www.borla.com/media/installation_instructions/A-35697.pdf