The exhaust manifold found on the 1988-2000 Honda civic and crx d15/d16 sohc 4 cylinder engines were designed to combine the exhaust gasses from each of the cylinders quickly with a manifold that was cost effective to produce. Our 4-2-1 tri-y off-road racing headers are designed to allow the exhaust gasses to flow more freely from each cylinder and combine in a more efficient manner. Tubing has been optimized for the 1.5l and 1.6l engines. This creates a reduction in cylinder backpressure and improved exhaust gas velocity. These improvements free up lost horsepower and torque. An added benefit is a more performance oriented exhaust sound. Package included: - 1 x set of header exhaust system, gasket (s) and bolt (s) (all if any is necessary for installation) compatible with: - 88-00 Honda civic d-series - 88-91 Honda crx d-series - 93-97 Honda del sol d-series notes: - Fits d18 overseas models with slight modification.