2017–2019 Audi A5 S-Line / S5 B9 Coupe & Sportback S5 Style Rear Bumper Diffuser – Carbon Fiber

Upgrade the lower rear profile of your Audi A5 S-Line or S5 B9 with this carbon fiber rear bumper diffuser. Finished in deep gloss black carbon and spanning 150 cm across the lower bumper, the S5-style profile adds width and visual aggression for a more planted, performance-oriented rear stance.

Build

• Material: Genuine carbon fiber, manufactured to precise tolerances for consistent panel quality, high structural integrity, and an authentic weave appearance over carbon-look ABS or fiberglass alternatives
• Surface finish: Deep gloss black finish with a UV-resistant coating that showcases the natural carbon weave and resists UV exposure, moisture, and road debris through sustained outdoor and driving use
• Configuration: Single-piece diffuser for the lower rear bumper
• Panel width: 150 cm across

Design & Aerodynamics

• S5-style profile: Clean, factory-derived diffuser shape that brings the S5 rear-end look to the A5 S-Line
• Aggressive stance: Adds width and visual weight to the lower rear for a more planted, track-inspired rear end
• Carbon aesthetic: Directional weave and gloss black finish complement the factory B9 bodywork for a coordinated, motorsport-grade look

Fitment

• 2017–2019 Audi A5 S-Line B9 — Coupe (2-door) and Sportback (4-door)
• 2017–2019 Audi S5 B9 — Coupe (2-door) and Sportback (4-door)
• Fits the A5 S-Line and S5 factory rear bumper only — not compatible with the standard non-S-Line A5, aftermarket bumpers, or non-B9 configurations
• Confirm your body style before ordering — verify whether your car is the Coupe or Sportback and check the rear bumper configuration matches

Package Contents

• 1 × carbon fiber rear bumper diffuser
• Installation hardware

Installation

• Surface prep: Thoroughly clean and degrease the rear bumper before installation to ensure correct panel seating and secure fitment
• Alignment: Dry-fit and check the diffuser sits centred and even across the bumper, with consistent panel gaps on both sides, before final fitting
• Professional installation recommended for correct positioning, panel alignment, and finish quality given the 150 cm panel width
• Plan for a second pair of hands during fitting given the panel's span

Before You Install

• Confirm your car is an A5 S-Line or S5 B9 (2017–2019) before ordering — this will not fit the standard non-S-Line A5
• Verify your body style and rear bumper shape against the product images before ordering, as the Coupe and Sportback rear ends differ
• Take care when parking rear-in — full-width lower rear panels sit close to kerbs and parking blocks