This system will fit vehicles with and without NPP. BORLA(r) system does NOT include NPP valves. System features 4" polished T-304 stainless steel tips. ATAK(r), Acoustically-Tuned Applied Kinetics, technology is based on specifically-tuned attributes of the internal muffler cores, which are calibrated on a vehicle-by-vehicle basis to deliver the most desirable sound. This is our most aggressive sound. Even though the sound on the exterior is uncompromising, the sound in the cabin is devoid of harsh resonance, a product of painstaking engineering and over 40 years of experience. 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-controlled 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 world's most experienced (and most winning) exhaust brand.