This 2.5" diameter True Dual Borla(r) Cat-Back(tm) system as designed specifically for the Q50. It features a merge X-Pipe and Borla(r)'s patented Polyphonic Harmonizer technology for increased performance and improved sound. Borla(r)'s Polyphonic Harmonizer Technology utilizes patented units that contain pipes of different diameters and lengths to create multiple exhaust notes that harmonize to deliver a clean rich full-bodied sound. Completely eliminating the turbulent center intersection of a standard X-Pipe The classic S-Type sound level delivers a sporty sound and a deeper tone without any drone inside the cabin. The system has a single 4.5" bright chrome on T-304 stainless steel tip on each tail pipe. Systems with black chrome on T-304 stainless steel tips and carbon fiber tips are also available. Cat-Back(tm) & Axle-Back exhaust systems feature patented straight-through and multi-core technology to unleash hidden horsepower. Increased exhaust velocity adds power driving excitement fuel economy and the distinctive Borla(r) Sound of Power respected by motoring enthusiasts everywhere. Each system is built from premium high-quality T-304 austenitic 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 a flow & power and precision computer numerical control (CNC) manufacturing ensures an accurate fit. Best of all Borla(r) stands behind every system with a Million-Mile Warranty. Just what you'd expect from the worlds most experienced (and most winning) exhaust brand.