
SLN B58 Super 5" Ceramic-Coated Sports Cat Downpipe – BMW M140i, M240i, 340i, 440i & 540i
SLN B58 Super 5" Ceramic-Coated Sports Cat Downpipe – BMW M140i, M240i, 340i, 440i & 540i replaces the restrictive factory catalyst section with a higher-flow sports-catalyst arrangement. It is intended to improve exhaust flow and turbo response while retaining a catalytic element and a more controlled exhaust note than a fully catless setup.
Key features
- Super 5-inch high-flow sports-cat design
- Ceramic-coated stainless-steel construction
- Retains a catalytic element while increasing flow
- Gen-1 B58 fitment/interface must be confirmed
BMW fitment
M140i, M240i, 340i, 440i & 540i.
Fitment check: BMW used different flange and connection arrangements across model years and engine revisions. Please confirm the engine, chassis and physical interface before ordering if there is any uncertainty.
Road-use / emissions note
A high-flow sports catalyst is not automatically EC type-approved for road use. Suitability and MOT/emissions compliance depend on the exact component and vehicle configuration. Please confirm the approval status before ordering for a road car.
Supply and fitting
Available from Swift Performance with fitment advice before ordering. Workshop fitting can be discussed where the component and vehicle remain suitable for road use.

