For higher horsepower cars TOMEI tested all various types of exhaust pipe diameter combinations & found the best combination of 42.7mm (pre gathering section), 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 WRX/STI turbo. This unit was designed for the Japanese Spec-C twin-scroll turbo which was not supplied from factory on any Australian vehicle. An aftermarket Twin-Scroll turbo or Factory Spec-C STI Twin-Scroll turbo will be required, as well as a compatible Twin-Scroll down-pipe. This version has larger piping and is meant for cars with aftermarket turbochargers.

Specifications

Includes Catalytic Converter: No

Installation Hardware Included: Yes

Manifold Design: Equal Length

Manifold Type: Twin Scroll

Piping Coating: No

Piping Flex Joing: No

Piping Material: 304 Stainless Steel

What's Included

• Twin-scroll Headers
• Twin-scroll Up-Pipe
• Gaskets
• Heat Wrap with Straps
• Fitting kit