Audi A5 S-Line / S5 B9 Sportback 4-Door Carbon Fiber Rear Bumper Diffuser Lip 2020 - 2021

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

• 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
• 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
• Configuration: Two-piece set for complete lower rear bumper coverage
• Panel width & weight: 173.8 cm across · approximately 1.65 kg for the set

Design & Aerodynamics

• Aggressive stance: Diffuser lip profile adds visual width and weight to the lower rear for a more commanding, track-inspired rear end
• Full-width coverage: The 173.8 cm span covers the complete lower rear bumper for an integrated finish with no exposed factory sections
• Carbon aesthetic: Directional weave and gloss finish complement the factory B9 Sportback bodywork for a coordinated, motorsport-grade look

Fitment

• 2020–2021 Audi A5 S-Line B9 Sportback (4-door)
• 2020–2021 Audi S5 B9 Sportback (4-door)
• Fits the factory rear bumper only — not compatible with aftermarket bumper configurations
• 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

• No-drill, adhesive-mounted: Installs with the included adhesive tape — no drilling and no permanent modification to the factory rear bumper
• Surface prep: Thoroughly clean, degrease, and dry the rear bumper at all mounting positions before fitting to ensure maximum adhesion
• Alignment: Dry-fit both pieces together and check spacing and symmetry across the full width before committing either to adhesion
• 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