Milltek Sport OPF/GPF-Back Rear Exhaust, GT-115 Cerakote Black Tips, BMW 128ti / 128 ti (F40) 1 Series 5-Door 2021+ | T304 Stainless Performance Back Box Axle-Back | Filter-Back UK Made | SSXBM1203

Filter-back rear section with GT-115 black ceramic finishers for BMW 128ti F40 five-door, 2021 on

Give your hot hatch the voice it deserves with this UK-built stainless rear system. Crafted for the BMW 1 Series 128ti on the F40 platform, this filter-back upgrade sharpens throttle response, deepens the note and adds a purposeful, sporty tone while keeping motorway manners calm and refined. It retains the factory particulate filter hardware for straightforward compatibility and a hassle-free upgrade.

Part number: SSXBM1203

What you will love

• Designed specifically for BMW 128ti F40 five-door models from 2021 with OPF or GPF fitted
• Filter-back layout keeps emissions equipment in place for a clean, bolt-on install
• T304 grade stainless throughout, corrosion resistant and built for long-term use
• Free-flow, mandrel-formed pipework for smooth gas velocity and crisp response
• Carefully sized tubing for performance without flattening mid-range torque
• Acoustically tuned for a deeper, sportier soundtrack with minimal cabin boom
• GT-115 black Cerakote tailpipe finishers for a stealthy, motorsport-inspired look
• Direct replacement for the OE rear section, no cutting of the filter required

Engineering that delivers

Precision-formed T304 stainless steel resists heat cycling and discolouration, with welds and bends executed to tight tolerances for consistency. The constant-radius bends preserve internal diameter through every curve, helping the B48-powered 128ti breathe more freely and feel keener across the rev range.

Sound you can live with every day

On the move, you get a richer bass at idle, a cleaner top-end note under load and near-zero drone at cruising speeds. It is the ideal balance for daily driving, back-road fun and long trips alike, enhancing character without tiring resonance.

Compatibility

• Vehicle: BMW 1 Series 128ti, F40 chassis, five-door
• Years: 2021 onwards
• Configuration: cars equipped with OPF or GPF
• System type: filter-back rear section
• Tailpipe style: GT-115 black Cerakote coated tips
• Part number: SSXBM1203

Tried and recommended by MJ Modifications

We have fitted this system to multiple customer 128ti builds and the feedback has been consistently positive. Owners praise the quality, the stealthy black outlets and the way it boosts character without compromising day-to-day refinement.

Professional fitting available

Want a supply and fit package by specialists who know the F40 inside out? MJ Modifications in Warwickshire can install this system and advise on complementary upgrades. Request a quote at info@mjmodifications.co.uk.

Search terms to help you find the right upgrade

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