HKS | High Flow Sports-Cat Downpipe | Honda Civic Type R | FK8/FL5 2.0T K20C1 | 2017+The HKS 150 cell sports cat downpipe is designed to maximise flow and reduce exhaust pressure. The layout follows the stock catalyst design. Using data from the genuine catalysts, repeated trail and error tests were conducted to pursue performance goals. Targeting flow bench testing and internal exhaust emission compliance testing. By enlarging inner diameter and reducing the catalyst cell count to 150 cells, achieves the lowest possible exhaust back