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ASIGN Genuine Carbon Fiber Replacement Rear Diffuser for Audi A4 / S4 Sedan

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ASIGN · Audi A4 / S4 Sedan

Give Your Audi a Sharper Rear Profile

Bring genuine carbon fiber detail to the lower rear bumper. This replacement rear diffuser takes the place of the factory diffuser for a more purposeful rear view.

Genuine Carbon FiberReplacement InstallationSedan Only

Real Carbon Detail

Add carbon fiber texture and visual contrast where the rear bumper meets the exhaust.

Integrated Placement

The original lower diffuser is removed so the new piece occupies its position.

A Finishing Touch

Give the rear end its own focal point or complement your existing carbon fiber accents.

Choose Your Version

Start with the U.S. model-year guide below, then confirm your rear bumper and exhaust layout. A year match alone does not confirm fitment.

Listing option group U.S. sedan model years
2009–2016
B8 / B8.5
A4: 2009–2016
S4: 2010–2016
2017–2019 · V1 / V2
B9
A4: 2017–2019
S4: 2018–2019
2020–2024 · V1 / V2
B9.5
A4 / S4: 2020–2024

Before ordering: Match the selected option photos to your bumper and exhaust openings. For V1/V2 selection or fitment help, send your model, year, trim and a clear rear photo. Mention any bumper or exhaust modifications.

Body style: Sedan only. Excludes Avant/wagon, Allroad and Cabriolet models.

Replacement Installation

  1. Remove the factory lower diffuser.
  2. Test-fit the replacement and check mounting points, edge alignment and exhaust clearance.
  3. Secure it using the attachment method specified for your selected version.

Professional installation is recommended. Request the installation guide for your version before fitting.

Product Details

Material
Genuine carbon fiber
Included
1 rear diffuser in the selected version
Position
Lower rear bumper
Installation type
Replacement

Quick Answers

Will it fit both standard and S line bumpers?

Do not assume both use the same diffuser. Confirm the bumper shape and mounting layout against your selected version before ordering.

How do I choose between V1 and V2?

Compare the option photos and have us check them against your rear bumper and exhaust layout.

Will my current exhaust tips fit?

The opening shape, tip position and clearance must match. Include exhaust details when requesting a fitment check.

Does the original diffuser stay installed?

No. This replacement takes its place; the original diffuser must be removed.

Get the Right Rear-End Upgrade

Confirm your bumper, choose your version and complete the rear view. Ask ASIGN to check your fitment .

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Asign Genuine Carbon Fiber Replacement Rear Diffuser / Rear Lip for Audi A4 / S4 Sedan (Multi-Gen Fitment | 2009-2024) Asign Genuine Carbon Fiber Replacement Rear Diffuser / Rear Lip for Audi A4 / S4 Sedan (Multi-Gen Fitment | 2009-2024) Asign Genuine Carbon Fiber Replacement Rear Diffuser / Rear Lip for Audi A4 / S4 Sedan (Multi-Gen Fitment | 2009-2024) Asign Genuine Carbon Fiber Replacement Rear Diffuser / Rear Lip for Audi A4 / S4 Sedan (Multi-Gen Fitment | 2009-2024) Asign Genuine Carbon Fiber Replacement Rear Diffuser / Rear Lip for Audi A4 / S4 Sedan (Multi-Gen Fitment | 2009-2024) Asign Genuine Carbon Fiber Replacement Rear Diffuser / Rear Lip for Audi A4 / S4 Sedan (Multi-Gen Fitment | 2009-2024)
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Frequently Asked Questions
What makes Asign different from other brands?
Asign stands out by offering meticulously designed carbon fiber kits that fit seamlessly with a variety of vehicle models. Our commitment to precision, use of high-quality materials, and focus on ease of installation set us apart in the market.
Why should I choose Asign's carbon fiber kits?

A1: Precision Design & Fit

Our design process strictly follows original vehicle specifications to ensure a perfect fit for your car. We approach each product with exceptional care and attention to detail.

A2: High-Quality Materials & Manufacturing
Asign uses the highest precision steel molds for production, reducing errors and maximizing accuracy. We employ pre-impregnated carbon fiber for all our products, making them genuine and lightweight, yet as strong as steel.

A3: Easy Installation & Non-Destructive Removal
Most of our carbon fiber kits can be installed in under 10 minutes (excluding special items like Front Splitters, Rear Diffusers, and Exhaust Tips). Designed for quick installation and removal without damaging your car's surface, our products offer both convenience and flexibility.

How does Asign ensure product quality?
Asign upholds strict quality control standards throughout the production process. We use premium materials and advanced manufacturing techniques, followed by comprehensive testing to ensure every product meets our high standards for performance and durability.
What if I have a quality issue with my product?
If you encounter any quality issues with your Asign product, please contact our customer service team right away. We will promptly address your concerns and offer solutions, including replacements or refunds, as appropriate.
How can I make sure the product I order fits my vehicle?
Before placing an order, carefully check your vehicle's specifications and refer to the product description for compatibility information. If you have any questions or concerns, our customer service team is always available to provide personalized advice and guidance.
What is Asign's return policy?
Our return policy varies depending on the specific product and the reason for the return. Please refer to our website or contact our customer service team for detailed information on our return and exchange procedures.