2020–2021 Audi A5 S-Line / S5 B9 Sportback Rear Bumper Diffuser Lip – Carbon Fiber
Complete the rear-end transformation of your Audi A5 S-Line or S5 B9 Sportback with this carbon fiber rear bumper diffuser lip. Supplied as a two-piece set spanning the full lower bumper width, it adds visual width and a more aggressive lower rear appearance with a genuine carbon weave finish.
Build
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Material: Genuine carbon fiber, autoclave cured using a 3D design and CNC milling process for precise diffuser geometry, consistent panel quality, and an authentic weave appearance over carbon-look ABS or fiberglass alternatives
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Surface finish: High-gloss epoxy-polished top coat that showcases the natural carbon weave and provides lasting UV and moisture protection through sustained outdoor and driving exposure
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Configuration: Two-piece set for complete lower rear bumper coverage
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Panel width & weight: 173.8 cm across · approximately 1.65 kg for the set
Design & Aerodynamics
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Aggressive stance: Diffuser lip profile adds visual width and weight to the lower rear for a more commanding, track-inspired rear end
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Full-width coverage: The 173.8 cm span covers the complete lower rear bumper for an integrated finish with no exposed factory sections
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Carbon aesthetic: Directional weave and gloss finish complement the factory B9 Sportback bodywork for a coordinated, motorsport-grade look
Fitment
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2020–2021 Audi A5 S-Line B9 Sportback (4-door)
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2020–2021 Audi S5 B9 Sportback (4-door)
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Fits the factory rear bumper only — not compatible with aftermarket bumper configurations
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Body style: Sportback (4-door) only — does not fit Coupe, Sedan, or Cabriolet body configurations
Package Contents
- 2 × carbon fiber rear bumper diffuser lip pieces
- Pre-applied adhesive tape for installation
Installation
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No-drill, adhesive-mounted: Installs with the included adhesive tape — no drilling and no permanent modification to the factory rear bumper
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Surface prep: Thoroughly clean, degrease, and dry the rear bumper at all mounting positions before fitting to ensure maximum adhesion
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Alignment: Dry-fit both pieces together and check spacing and symmetry across the full width before committing either to adhesion
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Professional installation strongly recommended — a panel of this width requires careful positioning to achieve symmetrical alignment and a clean finish
Before You Install
- Confirm your car is an A5 S-Line or S5 B9 Sportback (2020–2021) before ordering — this will not fit the Coupe, Sedan, or Cabriolet
- Work in moderate temperatures and allow the adhesive to cure fully before washing the car
- Installation is reversible, but adhesive removal and re-prep may be required if pieces need repositioning
