4-Inch High-Flow Catted Downpipe

The Evolution Racewerks Sports Series 4" High Flow Catted Downpipe is engineered for N20 engines, specifically fitting 2012+ BMW 320i, 328i, 420i, and 428i models. Constructed from 100% 304-grade stainless steel, it features mandrel-bent 4-inch piping, 100% TIG-welded seams for enhanced durability, and a precision CNC machined turbocharger V-Band flange. This downpipe incorporates a high-flow 200-cell metallic catalytic converter, offering improved exhaust flow over the factory 400-cell ceramic core for increased horsepower, torque, and faster turbo spool. The design includes a stainless steel flex section, mirroring the factory setup to allow for proper exhaust movement and prevent undue stress on exhaust components and the turbocharger. This feature contributes to long-term durability and reduces the risk of stress failures. The downpipe is compatible with both factory and aftermarket exhaust systems, and it comes with all necessary hardware for installation. Optional add-ons include a high-temperature black ceramic thermal coating to reduce underhood temperatures and improve exhaust flow velocity, as well as additional O2 and EGT sensor bungs for wideband or EGT gauges, respectively. These bungs come pre-installed with plugs for future use. **IMPORTANT RESTRICTIONS:** This product is intended for OFF-ROAD COMPETITION USE ONLY and is not legal for use on pollution-controlled vehicles on public roads. It is available for sale in all 49 states, EXCLUDING CALIFORNIA. A Vehicle Compliance Waiver must be signed prior to purchase. This item is NOT FOR SALE, INSTALLATION, OR USE on licensed vehicles in the state of California. It is available for international customers without restriction. Installation is rated a 3 out of 5 for difficulty.