Alpha Performance R35 GT-R 90mm Catted MidpipeThe Alpha R35 GT R 90mm Catted Midpipe is one of the largest midpipes available on the market. DESCRIPTION Alpha R35 GT R 90mm Catted Midpipe The Alpha R35 GT R 90mm Catted Midpipe is one of the largest midpipes available on the market. Where most systems implement two 76mm (3) pipes that merge into a single 76mm (3) primary pipe, we offer a larger 90mm (3. 5) primary pipe to optimize exhaust gas flow. This reduces turbulence and unwanted back