K-Tuned - 8th Gen Civic Si Header Polished 409 Stainless Steel

Applications:  06-11 Civic SI Coupe and Sedan Note: *It is highly recommended to upgrade your rear engine mount to a Hasport rear mount to limit movement. *Donut gasket can be replaced by OEM Honda part (18229-PCX-003), you will have to reuse the metal ring. *A Tuned is REQUIRED for catalytic converter setup Features:- Fits Civic Si with K20Z3 engine.- 4-2-1 Tri-Y Design - 409 Series Steel- CNC cut 3/8" thick flanges- 2.5" OutletThe K-Tuned 8th Gen Civic SI Header was specifically designed to optimize the performance and power output of the K20Z3 engine that is found in all 2 and 4 door SI models. The header was developed using a proven 4-2-1 Tri-Y design that delivers power gains almost everywhere in the power band, not just the higher rpm range. Additional performance is accomplished by using large diameter piping to speed up the flow of exiting exhaust gases. We also use stepped piping and smooth transitions that minimize restriction. Fitment past the subframe and sway bar is pe