2017-2019 Audi A4/S4 — KB & S4 Style Rear Diffuser

Upgrade the rear of your 2017-2019 Audi A4 / S4 with your choice of two rear diffuser styles. Both are crafted from high-quality ABS plastic and designed for a clean, bolt-on fit using factory mounting points.

Style Options:

• KB Style — Aggressive multi-fin diffuser available in Black (primer-ready) or Carbon Fiber (hydrographic hydrodip). Fits both S-line/S4 and Non S-line trim levels.
• S4 Style w/ Exhaust Tips — OEM+ diffuser with integrated dual exhaust tip surrounds for a factory S4 look. Available for S-line and S4 trim levels only.

Key Features:

• Material: High-quality ABS plastic — primer-ready, paint to match or custom finish
• Designed for 2017-2019 Audi A4 / S4 using factory mounting points; may require fitment and trimming adjustments based on vehicle trim options — professional installation recommended
• Bolt-on installation — no cutting of the factory bumper required for standard fitment
• Fits A4 and S4 models only — not compatible with RS4

Fitment: 2017-2019 Audi A4 / S4 — B9. KB Style fits both S-line/S4 and Non S-line. S4 Style w/ Exhaust Tips fits S-line and S4 only (requires factory S-line rear bumper configuration).

The Carbon Fiber finish is a premium hydrographic carbon fiber hydrodip, pre-applied over ABS — no painting required.

Production & Lead Time: These rear diffusers are custom-manufactured to order. Please allow 1–2 weeks for production before your order ships. Orders cannot be modified or cancelled once production has begun.