Our range of Cast Downpipes offer further enhancements to gas-flow and heat management, being designed to increase efficiency and performance gains. The HJS High-Flow Sports Catalyst is the highest quality and best performing aftermarket catalyst. The quality of the product is made to reduce the density of OEM catalysts and be able to maintain emission regulations with daily usage. Standard OEM catalysts are usually 500-600 cells, our high flow catalyst reduces this to 200 cells. This makes the catalyst freer-flowing, improving gas-flow and performance.