Description

Anchor the rear aerodynamics of your WRX S4 with a definitive STI rear under diffuser. This aggressive component does more than just style; it actively manages underbody airflow to reduce drag and improve throttle response, embodying a full motorsport aesthetic.

Product Highlights

• Functional Aerodynamics for Responsiveness: The diffuser is engineered to improve the airflow behind the underfloor area. By accelerating and smoothing the air exiting from under the car, it reduces rear-end lift and turbulence, which contributes to improved vehicle responsiveness and high-speed stability.

• Aggressive Motorsport Image: With its pronounced, multi-fin design, it evokes a strong image of motorsports. The unit extends approximately 25mm rearward from the vehicle, creating a bold, technical, and purposeful rear profile that leaves no doubt about its performance intent.

• Bold Two-Tone or Stealth Finish:

  • Crystal Black Silica: Full stealth look.

  • Crystal Black Silica + Cherry Red: Features Cherry Red accents on the diffuser fins, creating a striking, high-contrast look that highlights the complex geometry.

Technical Specifications & Critical Warnings

• Product Name: STI Rear Under Diffuser for Subaru WRX S4

• Key Benefits: Functional Underbody Airflow Management, Aggressive Motorsport Styling, Choice of Finish

• Material & Finish: Resin, painted in Crystal Black Silica or Crystal Black Silica with Cherry Red accents.

• Dimensions: Extends ~25mm rearward from the vehicle.

• Warranty: Covered by the SUBARU genuine product warranty.

⚠️ Critical Compatibility & Usage Warnings:

• Exclusive Installation: Cannot be installed together with the Rear Bumper Skirt. It is a replacement for, not a supplement to, the standard aesthetic skirt.

• Significant Ground Clearance Reduction: Lowers ground clearance by approximately 25mm. Combined with its rearward extension, this makes the diffuser highly vulnerable to scraping on driveways, speed bumps, and steep transitions. Extreme caution is mandatory.