Supersprint Catless Turbo Down Pipes - BMW 3 Series F80 M3 | 4 Series F82/F83 M4NOT ROAD LEGAL Turbo downpipes for BMW F80 M3, F82 and F83 M4 Replace the OEM pre catalytic converters (catless downpipes or cat delete) The Supersprint downpipes are built in Aisi 304 Stainless steel, TIG welded and mandrel bent. They fit perfectly without any adaptation, with O2 sensor bungs, flanges and mounting brackets all matching the OEM parts. They are mostly responsible for the performance increase given by the Supersprint exhaust, thanks to