Elevate the performance of your BMW M240i, M340i, M440i, or X5 40i xDrive with the Untd. Performance 4.5″ Catless Downpipe. Designed for the powerful B58 3.0L I6 turbo engine, this high-flow catless downpipe replaces the restrictive factory catalytic converters, significantly improving exhaust flow and turbocharger efficiency. The result is a marked increase in horsepower, faster turbo spool, enhanced throttle response, and a deeper, more aggressive exhaust note, making it the perfect upgrade for your BMW.