2018–2019 Audi A4 B9 Sedan Rear Bumper Diffuser – Carbon Fiber
SHIPPING - RETURNS - WARRANTY - CANCELLATION POLICY
*** Market Conditions after 2020 have changed the landscape of automotive parts. Although we try to stock 1000's of items in our multiple warehouse and use multiple distribution channels, having back-orders are unavoidable in today's market. If you are in need of a product quickly, we suggest email, message, or call us for availability so that we may explore your options.
Email: Sales@Speedzoneweb.com
Call: 407-846-8430
Text: 407-749-6314
Frequently Asked Questions
2018–2019 Audi A4 B9 Sedan Rear Bumper Diffuser – Carbon Fiber
Transform the lower rear profile of your Audi A4 B9 Sedan with this carbon fiber rear bumper diffuser. Spanning 130 cm across the lower bumper, it adds width and a more aggressive lower rear appearance with a deep gloss carbon black finish that visually lowers and widens the rear stance.
Build
- Material: Genuine carbon fiber, autoclave cured and vacuum moulded using a 3D design and CNC moulding 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 finish in carbon black 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: 130 cm across
Design & Aerodynamics
- Aggressive stance: Diffuser profile adds width and visual weight to the lower rear for a more planted, track-inspired rear end
- Comprehensive coverage: The 130 cm span covers the lower rear bumper for a complete, finished rear-end upgrade
- Carbon aesthetic: Directional weave and gloss black finish complement the factory B9 bodywork for a coordinated, motorsport-grade look
Fitment
- 2018–2019 Audi A4 B9 Sedan
- Standard A4 only — does not fit the S4, which uses a different rear bumper
- Fits the factory rear bumper only — not compatible with aftermarket bumper configurations
- Body style: Sedan only — not confirmed for Avant or Allroad body styles
Package Contents
- 1 × carbon fiber rear bumper diffuser
- 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 before fitting to ensure maximum adhesion
- Alignment: Dry-fit and check the diffuser sits centred and even across the bumper before final adhesion
- Professional installation recommended for correct panel alignment and finish quality
Before You Install
- Confirm your car is a standard A4, not an S4 — this is moulded to the A4 rear bumper and will not fit the S4
- Verify your body style is the Sedan before ordering — fitment is not confirmed for the Avant or Allroad
- 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 the diffuser needs repositioning
Our History
For 26 years Speedzone Performance LLC has been providing aftermarket car parts to Central Floridians and 1000's of customers online. What makes us different than all the other places online? We have 3 actual brick and mortar locations where were serve customers daily and find new ways to provide support and assistance to the automotive community at large. From our in house SPDZ1 Brand, to our constantly growing in stock inventory, we strive to make our customer service and ease of purchase stand out from the rest! We are also one of the largest automotive part financing providers anywhere in the United States, and continue to provide more options for our customers every year. We love what we do, and it shows in every product we sell and every new customer who becomes a part of our Speedzone Family.