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MMD by FOOSE Rear Valance Diffuser (05-09 GT)

Item 387426
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$259.99 (each)

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      Video Review & Installation

      Hey guys, Stephanie with, and this is my review of the MMD by Foose Rear Valance Diffuser for 2005 to 2009 GT Mustangs. The MMD by Foose Rear Diffuser is going to be for those older S197 GT owners out there that are looking to change up the looks of the rear of the car but without having to cut away at the rear bumper or go to extreme with things. The MMD by Foose Rear Valance is designed to look like it could be a factory part but it still enhances the looks of the car at the same time. There isn't a whole lot out there right now that doesn't require some drilling or cutting. So first of all, this is an MMD by Foose part so it's actually designed by Chip Foose himself just like the other MMD by Foose items are. With that being said, this rear diffuser takes after the other MMD by Foose parts in the sense that once it's installed, it really just looks like it belongs. The S197 kind of has a plain rear end. I call it a little shapeless and the diffuser just gives the car a sharper look but it's not over the top or too crazy in my opinion. This is the only diffuser that's currently available that works with the stock bumper. There are some other options on the site but they do require replacing your whole bumper cover or a good amount of cutting or drilling. So this is really the only option that works with the stock bumper and just simply adds on. But that also means that if you get tired of it, you can always just pull it off and go back to stock and not have to worry about it. This is made from an ABS plastic which not only makes it look like an OEM part, but it's also intended to offer more durability and a longer lifespan than other materials which is good news for your daily drivers. It does have a factory style grainy texture that you can see right here, and if we flip if over, you'll see that there is 3M tape already pre-installed on the back to help make for an easier install, and there's also some support tabs. And when we do the install we'll show you more about those. From looking at it here and knowing about the construction, specifically that it's an ABS material, my overall impressions of this are that it's exactly what I expected. It is thin plastic at the end of the day, but it does seem like it's going to hold up against the weather and time on the road. Another thing that I like is that it does come with an alcohol prep pad to help get the surface as clean as possible and some adhesion promoter too. So you'll have everything that you need for the install when it comes time. When it comes to the price, this diffuser is going to run you right around the $250 mark. This is less expensive than the other alternatives that are out there, but this is really the only diffuser like I mentioned earlier. The nice thing about this is that it will match any car, it doesn't need to be painted, and it's ready to be installed right out of the box. When it comes to the install, luckily it's pretty straight forward. Like I said before, you don't need to do any drilling or cutting here. You only need one socket to mount the lower tab so you won't need a bunch of tools. So this install's really nothing complicated at all. The balance comes with the alcohol prep pads and the adhesion promoter and the 3M tape is already on the places that it needs to be. The only other thing that you might need is if you want to add some more 3M tape just to be safe, but it's not required. The first thing that you're going to want to do is make sure that the bumper where you're going to be installing the diffuser is as clean as possible. So that's what you use the alcohol prep pads for. After that, you'll put your support tabs on. And they are side-specific, so just note the orientation of them. Next, you'll put the adhesion promoter on, and you'll want the adhesion promoter anywhere that the diffuser tape makes contact with the bumper. But just as a side note, be careful with the adhesion promoter because it will leave a visible residue if you get it anywhere else other than your tape bonding area. After that, you're ready to get this thing on the car, and you want to start by pressing from the center of the bumper outwards. The last step will be mounting the lower tab and pressing the tabs against the diffuser for support. After all, you're probably looking at an hour or two tops and a one out of three wrenches on the scale. All right, so wrapping things up, the MMD by Foose Rear Valance Diffuser is a subtle way to make things a little different from your 'Stang. It doesn't require any cutting our drilling. It's made from a black ABS plastic so it fits in with a factory-like look. So if this is something that you like the looks of, feel free to check it out more online for yourself. I'm Stephanie, and for all things Mustang, keep it right here at

      Product Information

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


      • MMD by Foose Rear Valance Diffuser
      • Designed by Chip Foose
      • Aggressive Race Inspired Styling
      • Durable, Lightweight Thermo-Formed ABS Construction
      • Features a Factory Style Grained Texture
      • OEM Fit and Finish
      • Simple Straight Forward Installation
      • Fits 2005 to 2009 GT Mustangs with Factory GT Bumper Cover


      Custom FOOSE Styling. Designed by the talented and world renowned custom car builder Chip Foose using the original CAD data from Ford to ensure a precise fit, this MMD by Foose Rear Valance Diffuser will add an aggressive race inspired appearance to your late model 2005-2009 S197 GT Mustang.

      Quality Construction. Manufactured from OEM quality high impact thermoformed acrylonitrile butadiene styrene (ABS) plastic for superior durability, this MMD by Foose Mustang Rear Valance Diffuser features a factory style grained texture for an OEM appearance and to increase longevity against rock impacts from daily driving.

      Straight Forward Installation. Installation of the MMD By Foose Rear Valance Diffuser is quick and easy with NO drilling required. It simply attaches to the factory rear bumper cover using the supplied 3M doubled sided automotive bonding tape for a straight forward and secure installation.

      Application. This Modern Muscle Design by Foose Rear Valance Diffuser is specifically designed to fit the 2005-2009 GT Mustang models equipped with the stock rear bumper cover.

      MMD by FOOSE

      Fitment: 2005 2006 2007 2008 2009 Details

      MMD by FOOSE 387426

      CA Residents: WARNING: Cancer and Reproductive Harm -

      Installation & What's in the Box

      Installation Info

      What's in the Box

      • (1) Rear Valance Diffuser
      • Alcohol wipe
      • Adhesion promoter

      Tech Specs


      Customer Reviews (100+)

        Questions & Answers

        10 More Questions

        Will It Fit My Mustang

        • Bullitt - 08, 09
        • GT - 05, 06, 07, 08, 09