






Audi A4 B9 Avant Rear Diffuser Extension – Carbon Fiber
Audi A4 B9 Avant Rear Diffuser Extension – Carbon Fiber
Sharpen the rear end of your Audi A4 B9 Avant with this carbon fiber rear diffuser extension. Molded to follow the factory bumper lines, it adds lower-end definition for a lower, wider visual stance and a more performance-inspired finish.
Build
- Material: Genuine carbon fiber, lightweight and structurally durable, with an authentic weave appearance over carbon-look alternatives
- Manufacturing: Precision-moulded for accurate bumper fitment
- Surface finish: High-polish gloss carbon black finish with a protective clear coat
- Configuration: Single-piece diffuser extension for the lower rear bumper
Design & Aerodynamics
- Aggressive stance: Diffuser extension adds depth to the lower rear for a lower, wider, more planted stance
- Carbon aesthetic: Gloss carbon black weave and high-polish finish create strong contrast against the factory paint
- Factory-style integration: Precision-molded to the contours of the factory rear bumper for a clean, seamless fit
Fitment
- Audi A4 B9 Avant (8W5)
- Fits the factory rear bumper only — not compatible with aftermarket bumper configurations
- Body style: Avant (wagon) only
- Confirm your model and trim against the product images before ordering
Package Contents
- 1 × carbon fiber rear diffuser extension
- Installation hardware (adhesive tape and/or mounting screws)
Installation
- Two mounting options: Fits using the supplied adhesive tape and/or mounting screws for a secure fit
- Drilling may be required: If you use the screw option, screw fixing pierces the bumper, so it is a permanent modification rather than a reversible fit
- Surface prep: If using adhesive tape, 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 committing to either method
- Professional installation recommended for correct positioning, panel alignment, and a clean finish
Before You Install
- Confirm your car is an A4 B9 Avant before ordering — this is moulded for the Avant rear bumper
- Take care when parking rear-in — lower rear panels sit close to kerbs and parking blocks
- Adhesive installation is reversible, but removal and re-prep may be required if the diffuser needs repositioning
Ships within 1-2 business days.
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Audi A4 B9 Avant Rear Diffuser Extension – Carbon Fiber
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FAQs
Please read our FAQs page to find out more.
Are OEM products more expensive than aftermarket alternatives?
OEM products might have a higher upfront cost compared to aftermarket parts, but their superior quality and durability often make them a more cost-effective choice over time. Investing in OEM ensures you’re getting parts specifically designed for your vehicle, which can lead to better performance and longevity.
Can I purchase OEM parts online or do I need to visit a dealership?
You don’t need to visit a dealership to get OEM parts. You can conveniently purchase genuine OEM components from authorized distributors and reputable online retailers like Turbo Tech Performance. Our online store provides a wide selection of high-quality parts delivered straight to your door.
Are parts from brands like Mopar, ACDelco, and Motorcraft interchangeable between different vehicle brands?
No, parts from Mopar, ACDelco, and Motorcraft are typically designed for specific vehicle brands. It’s crucial to ensure compatibility with your vehicle’s make and model by checking part numbers and consulting with a knowledgeable expert.
Can I install OEM parts myself, or is it better to have a professional handle it?
While some OEM parts can be installed by DIY enthusiasts, the complexity of installation can vary. For the best results and to ensure proper fitment and performance, we recommend having a trained mechanic install the parts, especially if you’re unfamiliar with automotive repairs.
Do OEM parts come with a warranty?
Yes, many OEM auto parts come with a manufacturer’s warranty that covers defects or issues. Be sure to check the warranty details for each part at the time of purchase, and keep your receipt for any potential warranty claims.


