The Alpha R35 GT-R 90mm Race 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 pressure - freeing up horsepower and improving turbo response.