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RTR Rear Diffuser (15-17 GT Premium, EcoBoost Premium)

Item 387381
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Market Price $329.99 You Save 15% ($50.00)
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$279.99 (each)

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      Video Review & Installation

      Hey guys, Justin with here, with my detailed review of the RTR Rear Valance Diffuser, fitting your premium package 2015 and up Mustang. So, who is this rear valance going to be for? Well, I would say it's going to be for anyone out there who really enjoys what Vaughn and his team at RTR have done with the S550, in regards to overall styling, and maybe wants to emulate that on his or her own ride. In addition, I'd say it's an excellent option if you're like me and you really didn't enjoy the factory color-matched rear valance, and want to replace it with something that's going to be a little bit more aggressive. Now when talking with Vaughn directly about his inspiration for the new RTR Mustang, he made it very clear to me that he wanted to do something pretty crazy with the rear of the car and give it more of an exotic look, in his own words. So by going with this fin-style rear diffuser valance, he definitely accomplished that and gave it more of a race car-inspired look in the rear. Now I think personally this thing looks a lot better when paired with the RTR rocker splitters, but again that is up to you, as it is going to add roughly 300 bucks to the final price tag. On the topic of price guys, this thing is definitely going to come in at the top of the food chain in regards to rear diffusers. Here on the site, it will be nearly double the price of the Roush rear valance, however you have to keep in mind that Roush rear valance can only be used with a quad-tip exhaust setup, so you have to factor that into the price. On the other hand, the RTR rear diffuser here can be used with your factory or aftermarket single-tip exhaust system, so you don't have to worry about anything there. Breaking down some of the finer details here, guys, you will find a durable, injection-molded ABS plastic for the build, and it has been finished off in the same textured grain black plastic as the rest of the exterior plastic on your S550, such as the chin spoiler, lower rockers, things like that. I do want to remind you, this will only work on premium package rear bumpers, as they are a little different from some of the base cars, so definitely don't forget about that. And also keep in mind, this thing will work with factory backup sensors, should not interfere with their operation whatsoever. When it comes time to get dirty, guys, here's what you need to know. Now, there is some permanent modification needed to get this thing installed. Basically you're going to be cutting off that color-match portion of the factory valance and replacing it with the RTR unit here. So an air saw, Dremel, something similar is going to be your best friend here. You're definitely going to need a 7-millimeter socket, along with a panel removal tool. Now, it probably sounds a lot more complicated than it really is, but nevertheless since there is some cutting involved, I'll call it two out of three wrenches on the difficulty meter, and maybe a couple of hours from start to finish to get this thing installed. So to wrap up, the RTR rear diffuser, or rear valance, guys, I really like what this thing does to the rear of the car. My one major pet peeve with the S550 from an appearance standpoint when it was released, was that color-matched factory valance. This thing totally replaces that, fixes that, in my opinion, and adds some aggressive styling to boot. So be sure to check out more from RTR for your S550 here at

      Product Information

      Features, Description, Reviews, Q&A, Specs & Installation


      • RTR Signature Modern Aggressive Styling
      • Injection Molded TPO Material
      • Features a Grained Texture
      • OEM Fit and Finish
      • Straight Forward Installation
      • Backup Sensor Compatible
      • Fits 2015-2017 GT and EcoBoost Mustangs
      • Designed for Premium Chassis Packages Only (Trim Levels: 200A/201A/400A/401A)


      Ready To Rock! Install the same exact Rear Diffuser that is featured as original equipment on the Ford Mustang RTR to your very own late model muscle car. Designed and developed by Vaughn Gittin Jr., this Diffuser will add a modern, yet aggressive race inspired appearance to your ride.

      Quality Construction. RTR manufactures its Diffuser from OEM quality, high pressure injection molded, high-strength thermal plastic olefin (TPO) for its long lasting durability. This RTR Rear Diffuser features a grained texture for an OEM look and to hide rock and stone impacts that occur during daily driving.

      Straight Forward Installation. Installation of the RTR Rear Diffuser is simple and straight forward. However, it will require permanent modification to the stock rear bumper cover to remove the factory diffuser. Installation can be completed in about two hours.

      Backup Sensor Compatible. This RTR Rear Diffuser can be installed on Mustangs equipped with or without factory installed back-up sensors and will not affect sensor operation.

      Application. This RTR Rear Diffuser is specifically designed to fit 2015-2017 GT and EcoBoost Mustangs equipped with the factory Premium Chassis Packages only (Trim Levels: 200A/201A/400A/401A).

      Please Read. If you are having trouble determining what style bumper your Mustang is equipped with please refer to the comparison image above.




      RTR 387381

      CA Residents: WARNING: Cancer and Reproductive Harm -

      Installation & What's in the Box

      Installation Info

      What's in the Box

      • (1) Rear Diffuser

      Tech Specs


      Customer Reviews (97)

        Questions & Answers

        10 More Questions

        Will It Fit My Mustang

        • EcoBoost - 15, 16, 17
        • GT - 15, 16, 17

        Fits Premium Chassis Packages only (Trim Levels: 200A/201A/400A/401A)

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