Milltek Sport Muffler/Back Box Delete Axle-Back, Rear Silencer Straight Pipe, Non-Valved, GT90 Burnt Blue Titanium 90mm Twin Tips, BMW 1 Series 125i F20/F21 B48 2016-on, Fits M135i Diffuser/Valance, 3dr & 5dr Hatch Exhaust Upgrade

Milltek Sport rear muffler delete with GT90 burnt blue titanium tailpipes for BMW 125i F20 F21 B48 2016 onwards

Give your BMW 1 Series 125i the soundtrack it deserves with this Milltek Sport rear section. This silencer delete replaces the factory rear box on B48-engined F20 and F21 models, unlocking a deeper, more purposeful tone and a crisper turbo four soundtrack. Finished with stunning GT90 burnt blue titanium outlets, the twin 90 mm tips fill the bumper perfectly for a motorsport look that suits the 1 Series.

What you will hear and feel

• Noticeably louder than stock with a richer, throatier note under load
• Clean, refined sound quality at cruise with minimal cabin boom
• Straighter flowing rear section for improved gas velocity
• Retains factory catalysts and emissions hardware

Premium construction

• UK designed and hand finished by Milltek Sport
• T304 aircraft grade stainless steel for durability and corrosion resistance
• Mandrel bent tubing and precision TIG welding
• Fixed outlet design with no valve or flap for consistent tone
• GT 90 burnt titanium tailpipe finishers with a heat-tint blue sheen

Compatibility

• BMW 125i F20 3 door, B48 engine, 2016 onwards
• BMW 125i F21 5 door, B48 engine, 2016 onwards
• Requires the M135i style rear lower diffuser or valance to suit the 90 mm twin tips
• For B48 models only. Not suitable for earlier non B48 variants

Why enthusiasts choose this setup

We have fitted this Milltek rear section on multiple customer builds and our own demo cars. Feedback is consistently positive: excellent fitment, a more engaging exhaust character without harshness, and a high-end finish that looks incredible behind the bumper. The burnt blue titanium outlets elevate the rear end with an authentic performance aesthetic.

Installation

Professional fitting recommended. Book your install with MJ Modifications in Warwickshire. Email info@mjmodifications.co.uk for a quote, fitment checks and advice on M135i diffuser compatibility.

Key search phrases

BMW 125i F20 F21 B48 exhaust upgrade, 1 Series 125i muffler delete, BMW 1 Series rear box removal, Milltek 125i rear section, straight-through rear pipe 125i, twin 90 mm titanium tips BMW 1 Series, blue burnt titanium tailpipes GT90, B48 sound upgrade, F20 F21 axle rear section, M135i style diffuser compatible tips, BMW 1er 125i performance exhaust, 2016+ 125i hatchback exhaust, UK made stainless exhaust 125i, plug-in rear section 125i.

If you are unsure about diffuser compatibility or model year fitment, contact MJ Modifications and we will confirm before you order.