VRSF Downpipe Upgrade N55 2011 – 2018 BMW X3 35i & X4 35i F25/F26 (Racing Downpipes/ Cerakote High Temp Coating)VRSF Downpipe Upgrade BMW X3 35i & X4 35i N55 F25 F26 (Race Cerakote) The factory downpipe on the N55 X3 and X4 is a restriction that limits what these SUVs can do. The VRSF 3. 5" Race Downpipe eliminates that restriction with a direct bolt on design, delivering 20 25 horsepower gains with a tune, faster spool, and a more aggressive exhaust note. Available in race (catless) or 200 cell high flow catted configuration. Also available with Cerakote high