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Confidence Programme
Developed and inspected under a more disciplined quality direction, helping the buyer feel greater certainty in what they are ordering.
Audi A4 B9 S-Line / S4 Carbon Fibre Rear Diffuser with 3rd Brake Light
£559.00
ASM Sports Tech offers a precision-crafted diffuser tailored to fit the Audi A4 / S4 B9.
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Need Fitment or Product Guidance?
Speak directly with ASM Sports Tech for live WhatsApp assistance on fitment, lead time, compatibility, or build direction before ordering.
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Confidence Is Built Into the Direction.
Premium ownership does not begin at delivery. It begins with material discipline, fitment philosophy, and the confidence that every component belongs to a more serious product standard.
Assurance Standard
Trust should feel designed into the product experience — not added later as reassurance.
Every ASM Sports Tech component is presented through a more resolved ownership philosophy: cleaner development direction, stronger fitment intent, and more premium support before and after purchase.
View Confidence Programme
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OEM Precision Fitment
Engineered using 3D scanning and digital modelling to achieve cleaner fitment logic and stronger visual integration with the platform.
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Performance Engineering
Lightweight composite construction, premium finish discipline, and stronger structural intent all contribute to a more resolved ownership outcome.
Audi A4 B9 S-Line / S4 Carbon Rear Diffuser with Led
Give your Audi A4 B9 S-Line or S4 a dynamic, performance-driven upgrade with the ASM Sports Tech Carbon Fibre Rear Diffuser with Integrated 3rd Brake Light — designed to enhance aerodynamics and rear-end style with OEM precision.
Constructed from authentic carbon fibre, this diffuser combines ultra-lightweight strength with a flawless gloss finish. The integrated LED 3rd brake light adds a distinctive motorsport touch while improving visibility and safety. The aggressive fin layout optimizes airflow under the rear bumper, reducing drag and improving stability at speed.
Compatible Models:
- Audi A4 S Line (B9) 4-Door Saloon (2016 – 2019)
- Audi S4 (B9) 4-Door Saloon (2017 – 2019)
Features & Details
Premium Carbon Fibre Material
Enhance your Audi’s rear end with a lightweight, sturdy, and stylish carbon fibre diffuser that ensures longevity and a sleek appearance.
Aerodynamic Design
This diffuser is engineered to streamline airflow, improving fuel efficiency and reducing drag for an enhanced driving experience.
Integrated Rear Brake LED Light
The built-in LED light increases visibility, adding an extra layer of safety and a modern touch to your vehicle.
Easy Installation
Designed for a seamless fit on Audi A4 B9 S-Line and S4 B9 models, ensuring hassle-free installation.
Stylish Upgrade
Elevate your vehicle’s look with this aggressive yet elegant rear design, a must-have for any Audi enthusiasts.
Upgrade your Audi A4 B9 S-Line or S4 with the ASM Sports Tech Carbon Fibre Rear Diffuser with 3rd Brake Light, delivering a refined OEM+ aesthetic and genuine aerodynamic performance.
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Ownership Questions, Answered.
Clearer guidance before commitment. This section is designed to answer the final questions around fitment, installation, material direction, ordering, and support.
Compatibility is always based on the product title, listed fitment scope, and vehicle platform. If you are unsure before ordering, use the live WhatsApp support option and we can confirm the correct application before purchase.
Yes. Professional installation is strongly recommended, especially for carbon fibre aero parts, exhaust components, and platform-specific upgrades where alignment, finish protection, and correct hardware positioning matter.
Material specification depends on the product direction, but ASM Sports Tech focuses on stronger finish discipline, cleaner visual consistency, and more resolved platform-specific presentation across its premium programmes.
Lead time depends on whether the product is in stock, built to order, or part of a more exclusive production direction. The estimated timeline shown on the product page should be used as the main reference before checkout.
Yes. If you need help with fitment, visual direction, material choice, or build planning, use the WhatsApp consultation block on the page and we will guide you before you place the order.
Yes. Worldwide shipping is available across a wide range of ASM Sports Tech product lines. Shipping method and transit timing vary depending on product category, destination, and dispatch origin.
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Authorised Dealer Access
For selected regions and projects, ASM Sports Tech can also be approached through an authorised partner network. This creates a more local route into the ownership experience while maintaining the same product direction.
Global Route
Prefer a more local path into the programme?
If you are ordering internationally, planning a wider build, or simply prefer a more regional point of contact, dealer access can provide a cleaner route into the ASM Sports Tech product direction.
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Regional Access
Selected customers may prefer a more local path into the product programme through an authorised ASM partner.
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Project-Based Ordering
Wider builds and multi-part upgrade directions can often benefit from a more coordinated route before final order placement.
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Direct or Dealer Route
Whether you proceed directly with ASM Sports Tech or through an authorised partner, the objective remains the same: a more resolved ownership experience.
ASM SPORTS TECH
Complete Your Build
Continue the programme with matching components selected to complement the visual direction, fitment logic, and overall presence of the build.
