The exhaust manifold found on the 1998-2001 Corolla 1ZZFE 4 Cylinder Engine were designed to combine the exhaust gasses from each of the cylinders quickly with a manifold that was cost effective to produce. Our 4-1 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 1.8L engine. 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.<br><br><b>Package Included:</b><li>1 x Set of Header Exhaust System<br><br><b>Compatible with:</b><li>98-01 Corolla E110<li>Fits E110 Models with 1.8L 1ZZ-FE Engines ONLY