Tomei Exhaust Manifold (Unequal Length) - Subaru WRX FA20DIT 2015+Every flaw of the OEM header has been addressed and improvised during the development of the Tomei header, resulting in power gains you can feel throughout the powerband of the car. Unequal length runners on the headers achieve the unique boxer engine rumble. The OEM headers restrict air flow resulting in loss of power and efficiency. Tomei headers do not restrict air flow resulting in an increase in power and efficiency. Unlike the OEM headers, Tomei