Akrapovic Valved Titanium Axle-Back/Slip-On Line Exhaust Back Box for BMW M135i xDrive F40 (2019+) - Carbon Fibre Tips - ECE Approved, OPF/GPF Compatible, EU/UK Road Legal Sports Rear Silencer

BMW F40 M135i Valved Ti Rear Section with Carbon Tailpipe Finishers

Upgrade the soundtrack and response of your F40 hot hatch with a premium valved rear silencer in ultra-light Ti and stunning carbon tailpipe finishers. This axle-back system brings sharper throttle energy, a richer tone under load and on gear changes, and refined civility on the motorway, all without unwanted cabin drone. If you are searching for a BMW M135i F40 sports exhaust, valved back box, titanium rear section, or OPF safe upgrade for UK roads, this is the go-to choice.

What you will love

• Ultra-light titanium construction for a meaningful weight saving over the factory rear muffler
• Genuine carbon fibre tailpipe finishers that complete the rear of the car with a motorsport look
• Valve-controlled sound, featuring a robust in-house cast valve housing for precise operation and long-term reliability
• Deeper, more characterful tone from the 2.0 turbo four, with a higher frequency edge when you lean on it, and no droning in Comfort
• Clever Y-split design that manages flow from the OPF, maintaining pulse distribution and smooth gas velocity
• Optimised internal routing for real-world performance gains across the rev range

Measured gains

Proven on the dyno with the stock OPF in place:

• Up to 3.3 kW increase at 5,350 rpm
• Up to 5.9 Nm increase at 5,300 rpm

Looking to take it further later on? Pair with the optional Evolution Link Pipe Set SS to unlock additional headroom and an even more engaging note.

Sound, feel, and day-to-day usability

In Efficient or Comfort the valve keeps things civil, perfect for commuting. Open it up in Sport and the car comes alive with a crisp, higher-frequency rasp and a deeper core, enhancing the B48 character without being boomy. We have installed this setup on customer cars and feedback is consistently positive about the premium build quality, lighter rear end feel, and addictive sound.

Fitment and approvals

• Made for BMW M135i xDrive F40, 2019 onwards
• ECE type approved for road use in the UK and Europe
• OPF and GPF compatible, designed to work with the factory particulate filter
• Valve motors integrate with OE control for seamless driving modes
• Installation requires cutting of the factory exhaust, please review the instructions before starting

Why this is the upgrade enthusiasts search for

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Professional installation

For a flawless fit and valve set-up we recommend expert installation. MJ Modifications offers supply and fitting at our Warwickshire workshop. Request a fitting quote at info@mjmodifications.co.uk.

Elevate your F40 with a road-legal, OPF safe, valved titanium rear section that looks incredible and sounds even better. Order now to transform the character of your M135i.