Milltek Sport BMW 1 Series 125i B48 2.0T F20/F21 Axle-Back Exhaust | Rear Silencer/Backbox/Back Box/Muffler Delete (Non-Valved Straight Pipe) | T304L Stainless | Cerakote Black or Polished | SSXBM1131 / SSXBM1132

BMW 125i B48 F20 F21 Axle-Back Backbox Delete by Milltek Sport

Give your 1 Series the soundtrack it deserves with Milltek’s straight-through rear section for the 125i B48. This axle-back backbox delete replaces the factory rear can with precision T304L stainless pipework, unlocking a deeper, harder-edged tone and a more engaging drive without the complexity of valves. Built in the UK, engineered to fit, and available in two finishes, it is the go-to tail section for drivers who want a quality sound upgrade that bolts straight on.

We have installed this setup at MJ Modifications and customer feedback has been outstanding. Expect a richer idle, crisper throttle response acoustically, and a purposeful growl that adds real presence on the road while keeping things simple and reliable.

Key benefits

• Straight-through rear section for a more aggressive note and reduced rear box restriction
• Axle-back design that swaps the factory backbox for a performance tail section
• Crafted from high-grade T304L stainless steel for durability and corrosion resistance
• UK manufactured with TIG-welded construction and OE-style hangers for a clean, secure fit
• Direct bolt-on replacement of the original rear section for hassle-free installation
• Choice of finish to suit your build: Cerakote Black or Polished
• Backed by Milltek’s two year warranty

Compatibility

BMW 1 Series F20 F21 125i B48 2012+

Part numbers and finishes

• SSXBM1131 – Cerakote Black
• SSXBM1132 – Polished

Built to deliver

Milltek’s rear section is engineered to integrate neatly with the factory system while transforming the car’s character. The straight pipe design sheds the restrictive rear box, amplifying burble and adding a sharper, sportier edge under load. It is a robust, long-term upgrade thanks to 304L stainless construction and precise UK manufacturing standards.

Fitting and support

Want it installed by professionals? MJ Modifications offers fitting at our Warwickshire workshop. Request a quote at info@mjmodifications.co.uk.

Warranty

Milltek two year warranty.

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