2017-2019 For Audi A4 S4 B9 Diffuser With Tailpipe

Product Description

Overview

Transform the rear profile of your 2017–2019 Audi A4 B9 S‑Line or S4 with this S4 style rear diffuser. Designed specifically for the pre‑facelift B9 platform (2017–2019), this diffuser replaces your factory rear valance with the aggressive, sporty look of the S4 — featuring a gloss black UV‑stabilized ABS polymer construction, aggressive honeycomb design, and dual tailpipe exhaust tips.

The B9 generation brought sharp, modern styling to the A4/S4 lineup. This S4‑inspired rear diffuser builds on that foundation, giving your A4 S‑Line a more commanding presence from every angle while improving rear‑end aerodynamics. The diffuser is crafted of a UV stabilized ABS polymer to achieve its deep high gloss shine and provides an aggressive and sporty style that's sure to set your vehicle apart from the rest. Features a dual tip/dual outlet design to fit the factory and most aftermarket exhaust systems and is designed to accept exhaust tips up to 4" in diameter.

⚠️ Critical Fitment Note: This diffuser is exclusively for Audi A4 B9 S‑Line (2017–2019) and S4 models. It will NOT fit Non‑S‑Line (standard) A4 bumpers or facelift B9.5 (2020–2024) models. The rear bumpers are different between S‑Line and standard, as well as between pre‑facelift and facelift, making diffuser compatibility non‑interchangeable without verification. You must have the factory S‑Line exterior package for this to fit.

📌 Complete Conversion Kit: Includes rear diffuser, dual exhaust tips, self‑tapping screws, 3M VHB tape, and installation manual.

Aerodynamic Benefits: The sculpted honeycomb design helps smooth airflow, reduce turbulence, and enhance rear‑end stability at higher speeds.

Serving both individual enthusiasts (B2C) and businesses (B2B):
✅ US warehouse for fast shipping
✅ CE certified for quality assurance
✅ 1‑year warranty for peace of mind
✅ Factory direct – competitive pricing
✅ Dropshipping & wholesale programs available
✅ Custom OEM/ODM orders welcome

5 Key Features

1. Aggressive S4 Style Design
Give your A4 B9 S‑Line or S4 the sharp, sporty look of the S4. The aggressive dual‑outlet design and sculpted lines create a bold, OEM+ appearance that dramatically enhances the rear profile. This diffuser was engineered and designed specifically for the B9 chassis to add more aggression to the rear of your car while matching the factory appeal of your Audi.

2. Complete Kit with Dual Tailpipe Exhaust Tips
All‑in‑one conversion kit includes the rear diffuser and dual exhaust tips — everything you need for a full S4 style rear transformation. Features a dual‑outlet design (left + right) that fits factory and most aftermarket exhaust systems and is designed to accept exhaust tips up to 4" in diameter. Choose between polished stainless steel or black‑chrome finishes to match your personal style.

3. Premium Gloss Black UV‑Stabilized ABS Construction
Manufactured from high‑quality UV‑stabilized ABS polymer — the same material used in OEM bumpers and body parts. The deep high‑gloss black finish is UV‑protected to prevent fading, yellowing, or bubbling from harsh sunlight. No painting required — ready to install out of the box. A premium pre‑preg dry carbon fiber version is also available for those seeking ultimate weight savings and weave aesthetics.

4. Direct Fitment for B9 S‑Line (2017–2019) — No Drilling Required
Engineered for a perfect OEM+ fit onto Audi A4 B9 S‑Line and S4 rear bumpers using factory mounting locations. Designed for Sedan (Saloon) body styles. Installs with no drilling, cutting, or modification of any kind required. Simply remove your currently installed valance, line up all tabs, and lightly press the diffuser in place until the tabs click into position.
⚠️ Note: This diffuser is NOT compatible with Non‑S‑Line (standard) A4 bumpers or facelift B9.5 models. You must have the factory S‑Line exterior package to install this diffuser.

5. CE & TUV MATERIALGUTACHTEN Certified
This diffuser is CE certified, meeting European safety and quality standards for automotive aftermarket parts. It has also received TUV MATERIALGUTACHTEN certification, verifying material quality and safety for road use. The product is also EPR (France/Germany) compliant, meeting environmental responsibility regulations for packaging and waste management. The product arrives with a protective film — do not remove the protective film until you are certain the product fits, as removal will void the return policy. If you decide to paint the diffuser, primer must be used first.

Specifications

What's in the Box

• 1 × S4 style rear diffuser 

• 2 × Dual tailpipe exhaust tips

Installation Guide

Professional installation is strongly recommended — do not attempt DIY unless you are a qualified technician.

Installation Time: 1–2 hours | Difficulty: Moderate

Important Safety Notice: When working underneath your vehicle, always use approved jack stands. Never work under a car that is only supported by a floor jack.

Shipping & Returns

 20-Year Specialization: 158000+ bumpers installed since 2006.

• Shipping: Worldwide delivery. In-stock US orders ship within 1-3 business days. International orders: 22-25 business days. Free shipping & no sales tax(Continental US only).

• Returns: If the kit does not fit, arrives damaged, or you are unsatisfied, return it within 15 days as long as it remains uninstalled and unpainted – free return shipping for genuine fitment issues. Combined with our 1-year warranty, this risk-free policy gives body shops, resellers, and DIYers complete confidence when ordering For Audi facelift kits. Contact us for wholesale pricing and US stock availability.

• Warranty: 1-year warranty against manufacturing defects.

Frequently Asked Questions

Q1: Will this fit my 2017–2019 Audi A4?

A: Yes, if your vehicle is a B9 pre‑facelift (2017–2019) with the S‑Line sport bumper (or an S4). This diffuser will NOT fit Non‑S‑Line (standard) A4 bumpers or facelift B9.5 (2020–2024) models. The 2019–2023 facelift introduced revised bumper contours, making diffuser compatibility non‑interchangeable without verification.

Q2: How do I know if my A4 has S‑Line or Non‑S‑Line?

A: The S‑Line exterior package includes sportier bumpers, side skirts, and fender badges. If your A4 does not have these, you have the standard (Non‑S‑Line) bumper. S‑Line and S4 rear diffusers are physically incompatible with the standard A4 bumper.

Q3: Does this kit include exhaust tips?

A: Yes! The complete kit includes dual tailpipe exhaust tips, self‑tapping screws, and 3M VHB tape — everything needed for a full S4 style rear transformation.

Q4: Does the diffuser require painting?

A: No. It comes in a premium high‑gloss black UV‑stabilized finish — ready to install out of the box. UV‑protection prevents fading and yellowing. If you decide to paint it, primer must be used first.

Q5: Is drilling required for installation?

A: No drilling, cutting, or modification of any kind is required when using factory mounting locations. However, self‑tapping screws are recommended in corners and tabs for best fitment. The product requires the removal of the original diffuser; self‑tapping screws are needed to secure fitment of the new diffuser.

Q6: Is professional installation required?

A: Yes, strongly recommended. Professional installation by someone with aftermarket product experience is highly advised. We advise trusting installation to a qualified professional unless you are confident following the provided fitting manual.