2020–2021 Audi A4 S-Line / S4 B9 Rear Diffuser – Pre-Preg Dry Carbon Fiber
2020–2021 Audi A4 S-Line / S4 B9 Rear Diffuser – Pre-Preg Dry Carbon Fiber
Give the rear end of your Audi A4 S-Line or S4 B9 a sharper, more aggressive finish with this pre-preg dry carbon fiber rear diffuser. The 3D-contoured design adds depth and dimension to the rear bumper for a performance-inspired, high-end look.
Build
- Material: Pre-preg dry carbon fiber — the resin is pre-impregnated into the weave under controlled conditions before autoclave curing, giving exceptional strength with lightweight performance, a consistent weave, and a lighter finished component than standard wet carbon
- Manufacturing: Autoclave cured, precision 3D-contoured for accurate fitment
- Surface finish: Deep high-gloss clear epoxy finish that enhances the carbon weave clarity and protects against UV exposure and surface wear
- Configuration: Single-piece diffuser for the lower rear bumper
Design & Aerodynamics
- Aggressive stance: 3D-contoured diffuser profile adds depth and dimension to the lower rear for a more planted, performance-focused rear end
- Carbon aesthetic: Refined dry carbon weave and high-gloss epoxy finish deliver premium contrast against the factory paint
- Factory-style integration: Precision-molded to the contours of the factory rear bumper for a clean, seamless fit
Fitment
- 2020–2021 Audi A4 S-Line B9
- 2020–2021 Audi S4 B9
- Fits the A4 S-Line and S4 factory rear bumper only — not compatible with the standard non-S-Line A4 or aftermarket bumpers
Package Contents
- 1 × pre-preg dry carbon fiber rear diffuser
- Mounting screws for installation
Installation
- Screw-mounted: Secures with the included mounting screws for a secure, rattle-free fit
- Drilling required: Screw fixing pierces the bumper, so this is a permanent modification rather than a reversible fit
- Surface prep: Clean and degrease the rear bumper at the fixing locations before installation
- Alignment: Dry-fit and check the diffuser sits centred and even across the bumper before driving any screws
- Professional installation recommended for correct positioning, panel alignment, and a clean finish
Before You Install
- Confirm your car is an A4 S-Line or S4 B9 (2020–2021) before ordering — this will not fit the standard non-S-Line A4
- This is a permanent, screw-mounted fitment — dry-fit and confirm placement carefully before driving any screws, as holes cannot be undone
- Take care when parking rear-in — lower rear panels sit close to kerbs and parking blocks
Ships within 1-2 business days.
100% Genuine Parts
Fitment Guaranteed
2020–2021 Audi A4 S-Line / S4 B9 Rear Diffuser – Pre-Preg Dry Carbon Fiber
If you have any questions, you are always welcome to contact us. We'll get back to you as soon as possible, within 24 hours on weekdays.
-
Fast Shipping
1-2 days processing
4-5 days delivery -
Secure payment
Fast, safe, and secure payments you can trust.
-
Customer Support
Count on our 24/7 support -
here whenever you need us! -
Contact Us
Leave us a message at: +17034100852 or email us at: sales@turbotechperformance.com
Premium Parts
Fitment Guaranteed
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.