Carbon Fiber Rear Bumper Diffuser for 2017–2019 Audi A4 B9 Base Sedan
Designed for selected 2017–2019 Audi A4 B9 Base Sedan models, this carbon fiber rear bumper diffuser replaces the factory lower rear diffuser to give the B9 pre-facelift rear end a more defined and performance-inspired appearance.
This product is specifically intended for compatible A4 B9 Base Sedan rear bumper configurations. It is not intended for Audi A4 S line or S4 rear bumpers, which use different lower bumper designs.
Vehicle Fitment
Vehicle: Audi A4
Generation: B9 Pre-facelift
Model Years: 2017–2019
Body Style: Sedan
Bumper Type: Base rear bumper
Not compatible with Audi A4 S line or Audi S4 rear bumpers. Because bumper specifications can vary by trim and market, please confirm your vehicle configuration before ordering.
If you are unsure about fitment, send us your model year together with clear rear bumper photos. Our team can help review compatibility before purchase.
Carbon Fiber Construction
The diffuser is produced with 3x3 woven carbon fiber and finished with a gloss UV-protected clear coating. The exposed carbon weave is designed to complement other carbon fiber exterior upgrades while creating a more distinctive lower rear profile.
The UV-protected clear finish helps protect the visible carbon surface from normal environmental exposure while maintaining its gloss appearance.
Replacement-Style Rear Diffuser
This is a replacement-style rear bumper diffuser rather than an add-on lip. The factory lower diffuser is removed before the carbon fiber replacement is installed in its place.
The design follows the lower rear bumper area of compatible A4 B9 Base Sedan models and is intended primarily as an exterior styling upgrade. No specific downforce, drag reduction or handling improvement is claimed unless supported by product-specific aerodynamic testing.
Installation
Installation involves removing the factory rear diffuser and fitting the replacement carbon fiber unit. Self-tapping screws are included according to the current product specification.
Test-fit the diffuser before final installation and confirm that all mounting points and edges align correctly. Professional installation is recommended, especially if you are unfamiliar with bumper trim removal or panel alignment.
Confirm Your A4 B9 Rear Bumper Before Ordering
This product should be ordered based on the actual rear bumper configuration rather than model year alone. It is specifically positioned for the 2017–2019 Audi A4 B9 Base Sedan and should not be assumed to fit S line, S4 or later B9.5 bumper designs.
Explore More Audi A4 / S4 B9 Parts
Browse more 2017–2019 Audi A4 / S4 B9 parts, explore the complete Audi A4 / S4 collection, or view our full Audi carbon fiber parts range.
