This system will fit vehicles with and without NPP valves. BORLA® system does NOT include NPP valves. The single 2.5" diameter Into the muffler with dual 2" out Cat-Back™ system delivers the S-Type II sound which utilizes a muffler design that eliminates sound frequencies that are often associated with resonance or drone. The exhaust exits thru dual 4" round polished T-304 stainless steel tips on each muffler. BORLA® Cat-Back™ & 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® 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 flow & power, and precision computer numerical control (CNC) manufacturing ensures an accurate fit. Best of all, BORLA® stands behind every system with a Million-Mile Warranty. Just what you’d expect from the world’s most experienced (and most winning) exhaust brand.