Milltek BMW B58 G20 M340i xDrive OPF-Back Exhaust System
Transform the sound and presence of your BMW M340i with the Milltek BMW B58 G20 M340i xDrive OPF-back exhaust system. This EC approved, OPF-retaining performance exhaust is the go-to upgrade for G20 M340i owners who want a deeper, sportier tone and a premium quad-exit look without removing the OPF. Choose to keep your OE trim finishers or upgrade to Milltek Sport quad tips in ceramic black or polished for the perfect OEM+ or motorsport-inspired finish.
We have fitted and used this system on customer M340i builds and the feedback is consistently excellent. Fitment is clean, the sound is refined on the motorway and assertive when you want it, and the quality is exactly what you expect from Milltek. If you are searching for BMW M340i exhaust, G20 M340i exhaust upgrade, B58 exhaust, M340i OPF-back exhaust or Milltek Sport quad exhaust for BMW 3 Series, this system hits the brief.
Why choose this BMW M340i G20 Milltek exhaust
- EC approved design that retains the OPF for road-friendly compliance
- Direct OPF-back fitment for the BMW 3 Series G20 M340i xDrive B58
- Choice of finishers: keep OE trims or go quad exit with ceramic black or polished tips
- Engineered for improved gas flow and a richer, more engaging exhaust note
- Made in the UK and supported worldwide by Milltek Sport
- Designed by a brand with continuous R&D and proven results on modern BMW B58 platforms
Configurations and part numbers
- SSXBM1157 - OPF-back system to suit OE trim finishers
- SSXBM1159 - OPF-back system with Milltek Sport quad ceramic black tips
- SSXBM1158 - OPF-back system with Milltek Sport quad polished tips
Compatibility
BMW 3 Series G20 M340i xDrive Saloon with B58 engine, 2019 to present, OPF equipped.
*Requires OE system to be cut for installation.
Optional upgrade - Milltek cast downpipes with HJS high-flow sports catalyst
For owners looking to go further, Milltek’s cast downpipes offer enhanced heat management and gas flow. The HJS High-Flow Sports Catalyst uses a premium 200 cell core, significantly freer flowing than typical OEM 500 to 600 cell catalysts, helping maintain emissions compliance in daily use while improving performance potential. Pairing the OPF-back system with these components is a popular next step for B58 tuning.
Real-world feedback
We have installed this Milltek M340i OPF-back exhaust for customers and on our own projects. Owners love the improved tone, the quality fit and finish, and the option to run quad tips for a more aggressive factory-plus look. It is a highly recommended BMW M340i exhaust upgrade for daily-driven G20 cars.
Fitting and support
Professional fitting available at Nforcd in Warwickshire. Request a quote at Sales@nforcd.com.
Warranty
Milltek 2 year warranty on catalytic components and lifetime warranty on the downpipe.
Made by Milltek Sport
All Milltek performance exhaust products are designed and manufactured in the UK and distributed in more than 90 countries. Their continuous development programme ensures the BMW M340i G20 platform receives an exhaust that looks right, fits right and sounds right.
Search-friendly terms
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