The APR Cast Downpipe Exhaust System replaces the restrictive factory catalyst cross pipes and resonators with an upgraded 76mm stainless steel mandrel-bent system, featuring port-matched cast inlets, high-flow catalysts and various other features. Expect better throttle response, more horsepower and an intoxicating exhaust note, while remaining civilized during normal daily driving. It’s the best performance upgrade for the 4.0 TFSI following the APR ECU Upgrade and it’s all designed and assembled in-house, using premium materials and world-class manufacturing techniques few can match.