One of the bigger restricting components on the 370z is the exhaust system. Nissan figured this out when they redesigned the catback system for their Nismo 370z to adapt a more free flowing system which included, a redesigned H-pipe with dual outlets vs their Y-pipe with a single outlet, and a more free flowing muffler. With the revised exhaust system and a slight tweak to the ECU, Nismo 370zs gained 18 crank hp from the factory With the success of the Nismo exhaust, AAM Competition took this one step further and designed the S-Line Midpipe, a true 2.5” exhaust system connecting the factory catalytic converters to the stock rear muffler. The factory Nismo H-pipe and intermediate pipe starts off at 2 1/8” from the factory catalytic converters, opens up to 2 1/4” at the intermediate pipe, then taper back down to 2 1/8” by the time it hits the muffler. Although we would never doubt Nismo parts, we took on the challenge of designing a larger and more efficient system. The S-Line midpipe has been dyno proven to gain 20 hp to the wheels and 19 ft lbs of torque over a stock 370z, equipped only with our short tails, all else stock! AAM Competition S-Line Midpipe is handcrafted with mandrel bent 2.5” 16 gauge T-304 stainless steel. The system consists of a 2.5” H-Pipe and a 2.5” resonated intermediate pipe. This makes it perfect for those who want the added performance of an upgraded midpipe but want to keep the factory muffler to keep exhaust volume down, or those who already have our short tails and would like to continue the rest of their exhaust system.