Milltek Sport Cat-Back/Rear Exhaust for BMW 1 Series M135i F20/F21 N55 (2012+) - 3in/76mm 304 Stainless, Unvalved Axle-Back Back Box Rear Silencer, Twin 90mm GT90 Tips - Performance Sports Muffler Upgrade UK

Milltek Rear System for BMW 1 Series M135i N55 F20 F21

Give your M135i the soundtrack and response it deserves with this UK-made performance rear section from Milltek. Built from premium 304 stainless steel with smooth mandrel bends and a generous 3.00 inch 76.20 mm bore, it frees up gas flow, sharpens throttle feel and delivers a deeper, more purposeful tone compared to the factory setup. The twin 90 mm GT90 tailpipe finishers complete the OEM plus look many owners want for daily use and weekend blasts.

We fit these systems in-house and run them on our own cars. Feedback from our M135i customers is consistently positive on sound quality, fit and long-term durability. If you are hunting for a quality upgrade for your 1 Series hot hatch that balances refinement with excitement, this Milltek rear exhaust is the enthusiast choice.

Highlights

• Direct-fit rear exhaust for BMW 1 Series M135i with the N55 engine F20 5-door and F21 3-door, 2012 onwards
• Non-valved layout for a consistent, engaging soundtrack
• 3.00 inch 76.20 mm mandrel-bent pipework for efficient flow and responsive performance
• Twin 90 mm GT90 round tailpipes for a clean, factory-style appearance
• Lighter than the OE system and engineered for a crisper pedal feel
• Constructed from high quality type 304 stainless steel that resists corrosion and discolouration
• Designed and manufactured in the UK to ISO 9001 standards

Why it works on the M135i

The N55 turbo motor responds brilliantly to a freer-flowing rear section. The larger-bore pipework and carefully developed silencers enhance tone without the tinny resonance you get from lesser systems. It complements both stock and tuned setups, pairing nicely with common N55 upgrades while retaining everyday usability.

Fitment

Suits BMW M135i F20 5-door and F21 3-door, 2012 onwards, N55 engine. This is a non-valved system. During installation, unplug the factory exhaust valve and secure the wiring loom safely out of the way.

Installation and support

Direct replacement cat-back section with no fabrication required. Prefer professional fitting. Book with MJ Modifications in Warwickshire. Request a fitting quote at info@mjmodifications.co.uk.

Part numbers

• SSXBM964
• SSXBM965
• SSXBM966
• SSXBM967
• SSXBM1023
• SSXBM1024

Warranty

Milltek two year warranty for peace of mind.

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