For those aiming 800+hp and up we recommend our custom made Y- pipe kit. Long gone are the days of a blown Mafs which is the result of pushing the limit beyond the stock readings. It includes a complete overhaul of the stock Y pipe, air filter box, and plumbing. The intake system is made with 2.5″ OD tubing and is manufactured in house. The Y-pipe is made with 3.5″ tubing and tapers off to 2.5″ at the intercooler connection for those who desire 2.5″ vs. OEM intercooler connections which is also an option. We recommend using our 4.5″ race intercoolers for direct fit. All the welds are ported inside for maximum flow and the unit is hand polished to mirror finish. This complete system has been tested on a 1300hp porsche. It fits all after marker direct replacement turbos as well as most Gt30r/Gt35r applications.