Tomei Expreme Twin Scroll Exhaust Manifold Large Piping JDM - Fits Subaru STI 2004-2019

Tomei has always designed their headers with performance, reliability and quality in mind. Now they have a new model that is compatible with GDB, GRB and GVB. Introducing the highly acclaimed EJ twin scroll EXPREME header. With the very best of the Tomei exhaust technology, this new design will deliver balanced performance for optimised power, torque and feeling.

The September 2002 model Impreza STI was given a major upgrade with the introduction of the twin scroll turbo & all stainless steel equal length exhaust manifold. With the high performance potential of the new exhaust manifold it was said that development of an aftermarket exhaust manifold that could surpass the OEM manifold was impossible. However, at Tomei they challenged that claim and persistently tried to prove that claim false. With over 10 new test designs, Tomei thoroughly tested every single model. At last, they completed the Tomei EXPREME Large Piping exhaust manifold which greatly surpassed the OEM manifold in every way.

For high horsepower cars Tomei tested all types of exhaust pipe diameter combinations & found the best combination consisted of a 42.7mm pre-gathering section,a 45mm post-gathering section, and a 45mm uppipe.

These manifolds are manufactured using a Lost Wax process designed to eliminate cracking from welded weak points and for aiding smoother exhaust gas flow without any interference. Using 2.5mm thick pipes made from SUS304 stainless steel ensure you are getting one of the best pieces on the market today. 

This is a twin scroll manifold and will not bolt on to any stock USDM turbo. This unit was designed for the GD/GR/GV Chassis JDM STI's that had the factory twin scroll turbocharger. This version has larger piping and is meant for cars with aftermarket turbochargers.