BMW G-Series B58 OPF / GPF Sports Cat Downpipe (with Flex)

Built for BMW G-Series 3.0T B58 OPF/GPF models, this Promod Works sports cat downpipe is designed to reduce exhaust backpressure and improve flow where the factory system becomes restrictive. The result is sharper turbo response, stronger mid-range pull, and a more purposeful exhaust note — while still retaining a high-flow sports catalyst.

Why you’ll want it

Improves exhaust flow vs OEM for better response and performance potential

Helps reduce restriction on tuned / Stage 2-style setups

Sports cat design (cleaner than a decat option, less raw smell)

Adds a deeper, more aggressive tone without going full chaos

Key features

High-flow sports catalyst integrated into the downpipe

Flex section to reduce stress and movement-related cracking

Precision welded construction with a clean, OEM+ fit and finish (as pictured)

Sensor ports / mounting points positioned for OPF/GPF applications

Direct-fit style replacement for compatible B58 G-Series platforms

Vehicle fitment (B58 3.0T + OPF/GPF models only)

BMW (G-Series): G20/G21 M340i · G22/G23 M440i · G30/G31 540i · G32 640i GT · G01 X3 M40i · G02 X4 M40i · G05 X5 xDrive40i · G06 X6 xDrive40i · G07 X7 xDrive40i · G14/G15/G16 840i · G29 Z4 M40i · G42 M240i (where fitted with B58 + OPF/GPF — typically EU/UK spec, approx. 2019+)

Important notes (please read)

OPF/GPF only: This is intended for cars fitted with an OPF/GPF-equipped B58 setup. If you’re unsure, message us with your VIN / reg and we’ll help confirm.

May require ECU calibration depending on your setup and local spec (warning lights can occur on some cars).

Road legality/emissions: Motorsport/performance part — emissions and road legality vary by country and testing standard. Always check your local regulations and MOT requirements.