VRSF Race Downpipe Kit BMW 135i 335i N54 BrushedVRSF 3" Race Downpipe Kit BMW 135i 335i N54 (Brushed) The N54 twin turbo setup responds incredibly well to a downpipe upgrade. By eliminating the restrictive factory catalytic converters and reducing back pressure, the VRSF 3" Race Downpipe delivers faster spool, 20 25 horsepower and 25 30 torque gains at the wheels when tuned, and an exhaust note that matches the performance. Unlike competitors who neck down near the turbos, VRSF runs a full 3"