Skunk2 '02-'06 RSX, '02-'05 Civic Si Alpha HeaderNote: Complement with a genuine Skunk2 MegaPower Exhaust system for maximum exhaust flow. Includes adapter pipe, donut gasket, and oxygen sensor defouler. Race application; eliminates catalytic converter. O2 sensor bung thread pitch: M18 x 1. 5. Due to large packaging size, shipping rates are calculated based on dimensional weight. ***NOTE: Header WILL fit the EP3 Chassis but requires modification of the exhaust or the adapter to bolt up properly with