Supersprint Turbo Downpipe With De-Cat - BMW 1 Series F20/F21 M140I | 2 Series F22/F23 M240I | 3 Series F30/F31 340INOT ROAD LEGAL As an alternative to the "road" catted version (987311) Supersprint also offers a de cat option, for track use. This component drastically reduces the back pressure after the turbocharger, with beneficial effects on the temperatures and the gas flow. The absence of the catalytic converter requires the modification of the electronic management to avoid warning lights on the dashboard (CEL). All the characteristics of the 987311 (easy