BMW 3 Series G20/G21 Rear Diffuser - Genuine M Performance OEM Rear Bumper Insert/Lower Valance/Rear

Upgrade the back end of your BMW 3 Series G20 Saloon or G21 Touring with the authentic BMW M division lower rear valance, available in factory Gloss Black PUR or true Carbon Fibre. This OE accessory is the premium choice if you want a sharp, motorsport-inspired rear bumper insert with perfect alignment and a cohesive, factory-plus finish. If you have been searching for a BMW 3 Series rear bumper diffuser insert, M340i exhaust surround, G20 rear skirt, G21 lower apron, BMW OE rear valance or M Sport rear aero, this is the exact upgrade you are looking for.

Built by BMW for BMW, the finish quality and fit are exceptional. Choose High Gloss Black PUR for a deep, mirror-like shine that ties in with Shadowline trims, or select the hand-laid Carbon Fibre option for a performance aesthetic with visible weave and premium lacquer. We have installed these on customer cars and our own vehicles, and the transformation to the rear profile is immediate and impressive.

Why this OE rear valance is the right choice

• Authentic BMW OE accessory for exact fit and seamless integration
• Sporty, aggressive styling that looks factory fresh and premium
• Precisely contoured for the G20 Saloon and G21 Touring body shape
• Two finishes: High Gloss Black PUR or Real Carbon Fibre
• Gloss Black PUR is UV, temperature and water resistant for a lasting shine
• Carbon option features genuine weave for a true M Performance look
• Ideal for M340i, with wider compatibility on selected G20 and G21 models

Finish options

• High Gloss Black PUR: deep gloss that complements Shadowline and high gloss trims
• Carbon Fibre: real carbon weave with a premium, motorsport-led appearance

Compatibility

High Gloss Black Diffuser

• BMW 3 Series G20 Saloon (2017 - 2021)
  • 318d, 320d, 320dx, 320i, 320ix, 330d, 330dx, 330e, 330i, 330ix, M340i, M340ix
• BMW 3 Series G21 Touring (2018 - 2021)
  • 318d, 320d, 320dx, 320i, 330d, 330dx, 330i, M340ix

Please note: The High Gloss Black version requires the BMW 3 Series G20 G21 M Performance High Gloss Black rear bumper trim. There are two trims depending on model: one for 320d, 320i, 330d and 330i, and one for M340i and M340ix.

Carbon Fibre Diffuser

• BMW 3 Series G20 Saloon (2017 - 2021)
  • M340i, M340ix
• BMW 3 Series G21 Touring (2018 - 2021)
  • M340ix

Please note: The Carbon Fibre version requires the BMW 3 Series G20 G21 M Performance High Gloss Black rear bumper trim specifically for M340i and M340ix.

BMW part numbers

• 51192455821 High Gloss Black
• 51192459740 Carbon Fibre

Genuine BMW quality and warranty

Manufactured by BMW M Performance Parts with outstanding OE standards. Two-year manufacturer warranty when the VIN is provided at checkout.

Fitment check

We verify compatibility before dispatch. Provide your UK registration or the last 7 digits of your VIN at checkout and we will ensure the part suits your vehicle.

Professional fitting

For installation, we recommend MJ Modifications in Warwickshire. Request a fitting quote at info@mjmodifications.co.uk.

Proven on our cars and by our customers

We have fitted these original BMW rear valances to G20 Saloon and G21 Touring models. Owners love the factory look, the precise fit and the way it elevates the rear styling without compromising OE quality.

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