This system produced gains of up to 7 HP and 5 lbs. x Ft. TQ., as measured on our in - house dyno. This cat - back exhaust system is constructed of 3 IN to 2 - 12 IN mandrel - bent brushed finished 304 stainless steel tubing for maximum strength and durability. This system produces an aggressive sound unleashing all available horsepower and torque. Finishing off this exhaust system are quad 4 - 12 IN diameter polished stainless steel clamp - on exhaust tips. The tips features a laser etched aFe POWER logo for a unique style. Utilizing factory style flanges and hangers this system is a direct bolt - on system, which requires no cutting or modifications for a hassle - free installation. This cat - back exhaust system uses a heavy duty flex pipe with an internal interlock liner for added strength and durability. A mitered merge x - pipe is used to balance and evenly distribute exhaust pulses traveling through the exhaust system, minimizing exhaust drone and maximizing scavenging. This cat - back exhaust system incorporates factory style NPP dual mode AFM (active fuel management) exhaust valves which use the factory exhaust valve motors (not included). The valves helps regulate, direct and control the flow of exhaust gases by opening, closing, or partially obstructing passageways depending on throttle position for maximum performance. Utilizing state - of - the - art computer - aided design technology, this exhaust system is designed for custom, high tolerance factory fitment. 100 TIG - Welded for race - proven strength and durability.