KB Style Carbon Fiber Rear Diffuser w Brake Light - Audi A4 S4 RS4 Sedan ( 2020 TO 2025 ) B9.5

Complete the aggressive rear transformation of your Audi A4, S4, or RS4 B9.5 with the KB Style Carbon Fiber Rear Diffuser featuring an integrated brake light. This high-performance component replaces the factory rear valance with a sculpted, multi-fin design that optimizes underbody airflow for improved high-speed stability. The integrated central LED brake light adds a distinctive, motorsport-inspired detail, enhancing visibility and giving your B9.5 a commanding, track-focused rear presence.

Expertly crafted from autoclave-cured, high-gloss 2x2 twill carbon fiber, this diffuser offers superior strength and a significant weight reduction. Its flawless, UV-protected finish ensures long-lasting durability and showcases the premium carbon weave.

Key Features

• Precision fit for Audi A4, S4 & RS4 Sedan B9.5 (2020-2025)

• KB Style aggressive multi-fin design improves aerodynamic efficiency and rear-end stability

• Integrated LED brake light enhances safety and provides a motorsport aesthetic

• Manufactured from autoclave-cured, high-gloss 2x2 twill carbon fiber

• Pre-preg carbon construction for maximum durability and lightweight performance

• Direct-fit replacement for the factory rear valance

Production & Lead Time
Each rear diffuser is made to order, with a lead time of 6–8 weeks.

Lifetime Warranty
Includes a lifetime warranty against manufacturing defects.

Vehicle Fitment

• Audi A4 B9.5 Sedan (2020-2025)

• Audi S4 B9.5 Sedan (2020-2025)

• Audi RS4 B9.5 Sedan (2020-2025)

Note: Warranty is void if modified or installed outside AR Bodyworks.