Evolve Catless Turbo Downpipes - BMW 1 Series 135i | 1M | 3 Series 335i N54 Evolve Downpipe the ECU will need to

the ECU will need to be remapped when this downpipe is fitted to the Evolution Line exhaust system

Because the secondary O2 sensors will read the wrong values once these components are fitted

Supersprint front pipe with 100 CPSI metallic catalytic converter by HJS  Motorsport

Together with incredible weight savings

Evolve Catless Turbo Downpipes - BMW 1 Series 135i | 1M | 3 Series 335i N54 Evolve Downpipe the ECU will need toNOT ROAD LEGAL Evolve 3" catless turbo downpipes for the N54 1M 135i 335i in T301 Stainless steel. By eliminating the restrictive catalytic converters in the factory downpipes, back pressure is reduced significantly which results in faster spool, an increase in power & a more aggressive exhaust note. Features T301 Stainless Steel 3" Downpipe design with 2. 5" flange Gaskets and new bolts provided Fits both RHD and LHD Adds approx 10 BHP & 10 lb. ft