Unlock the true performance potential of your BMW M240i, M340i, M440i, or 540i/740i xDrive with the Untd. Performance 4.5″ Catless Downpipe. Designed for the B58 3.0L I6 turbo engine, this high-flow catless downpipe removes restrictive factory catalytic converters to improve exhaust flow, reduce backpressure, and enhance turbo efficiency. The result? Increased horsepower, quicker turbo spool, improved throttle response, and a more aggressive exhaust sound, making it the perfect performance upgrade for your F3X BMW.