Cast Downpipes are designed to enhance gas-flow and heat management, increasing efficiency and performance gains. The HJS High-Flow Sports Catalyst is engineered to provide high quality and optimal performance as an aftermarket catalyst. This product reduces the density of OEM catalysts while maintaining emission regulations for daily use. Standard OEM catalysts typically have 500-600 cells, while the high flow catalyst reduces this to 200 cells, resulting in improved gas-flow and performance. Milltek Sport is the sole UK distributor of HJS Tuning Catalysts. - Enhances gas-flow and heat management for increased efficiency - High-flow catalyst reduces cell count to 200 for improved performance - Maintains emission regulations for daily usage - Sole UK distributor of HJS Tuning Catalysts Specifications: - Pipe Diameter: 70.00 - Installation Time: 3 to 3.5 hours (including removing OE system) - Race Product: Yes - EMarked: No Kit comes with: - MSAU742: LH Cat Downpipe & GPF Bypass - MSAU742 - MSAU743: RH Cat Downpipe & GPF Bypass - MSAU743 Vehicle Compatibility: - 2019 and later Audi RS4 B9 2.9 V6 Turbo Avant (OPF/GPF Models) - 2019 and later Audi RS5 B9 2.9 V6 Turbo Coupe (OPF/GPF Models) - 2019 and later Audi RS5 B9 2.9 V6 Turbo Sportback (OPF/GPF Models)