Roush 2015-2017 Ford Mustang Premium Rear Diffuser, Pre-drilled for Back-up Sensors
This Roush Performance Rear Valance is designed to fit 2015-2017 GT and EcoBoost Mustangs equipped with the factory Premium Chassis Packages only (Trim Levels: 200A/201A/400A/401A).
Made in the USA at Roush’s own plastics manufacturing facility from OEM quality high-pressure injection molded high-strength thermal plastic olefin (TPO) for its long-lasting durability, this rear valance features a stippled-grained texture for an OEM look and to increase longevity against rock impacts from daily driving.
Not Prepped for Backup Sensors. This Roush Performance Rear Valance is designed explicitly for Mustangs without factory-installed back-up sensors. If your Mustang has back-up sensors, please use Roush part# 421919.
Required Upgrade. For proper installation of this Rear Valance, you will be required to upgrade to a Roush Quad tipped exhaust system. GT models will need Roush Part# 421920 or 421921, and EcoBoost models will need Roush Part# 421922 or 421923.
WARNING: Product may cause cancer and reproductive harm. To learn more please visit https://www.P65Warnings.ca.gov
We’ve got your back!
Function Factory Performance takes “customer service” very personally. We understand that finding the right parts can be overwhelming. Education and awareness are the principles that keep us ahead of the curve. Let us make this experience simple, easy, and awesome, so without hesitation give us a call at (480) 576-8606, feel free to direct message on our live chat, or CLICK HERE to contact us via email.
Make sure to follow us on Instagram: @FFPerformanceAZ and Youtube.
EMAIL A FACTORY SPECIALIST FOR HELP CALL A FACTORY SPECIALIST NOW
Frequently Asked Questions
For made-to-order or specialty items (like carbon fiber parts or custom builds), the turnaround can take up to 8 weeks — perfection takes time.
Either way, we’ll keep you updated so you know exactly when your parts are leaving the pit lane.
If your order ships via freight, you’ll get a separate email with a direct link to the carrier’s tracking page — easy and stress-free.
If your shipment is lost, just email or call us — we’ll help track it down and guide you through the next steps to make it right.
Follow us on Instagram, YouTube, and Facebook, and most importantly, drop us a review on Google or Yelp to let others know about your experience.
Your feedback helps us grow, create more content, and keep bringing performance-driven parts to the community.
First Class Customer Service
Customer service is our top priority. We know that finding the right parts can be overwhelming, so we’re here to make the process smooth and enjoyable. We’re always ahead of the curve with our commitment to education and awareness. Let’s make this experience simple and awesome together! Don’t hesitate to call us at +1 805 267 9762 or click here to reach us via email.
Make sure to follow us on Instagram: @FFPerformanceAZ and Youtube.
1
Customer Support Specialist
Have a question about parts or your order? We're open Monday to Friday, 9:00 AM to 5:00 PM PST.
Your Product Is Guaranteed
Our #1 responsibility is to deliver your parts as quickly as possible.
Race Proven Knowledge.
The crew at FFP is built from real racers and car enthusiast.
Payments Verified
We verify every transaction to prevent fraud. Know that your information is safe.















Reviews
There are no reviews yet