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MMD Rear Diffuser Fins (15-17 Non-Premium)

Item 394110
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    Features, Video & Details

    • Aggressive Race Inspired Styling
    • Smooth Matte Black Finish
    • Durable, Injection Molded ABS Construction
    • Simple Peel and Stick Installation
    • Fits 2015-2017 GT, EcoBoost and V6 Mustangs
    • Designed for Base (Non-Premium) Chassis Packages Only (Trim Levels: 050A/051A/100A/300A)

    Review & Installation Video

    Review & Install Video

    Hey guys, Stephanie with here with a review and install of the MMD Rear Diffuser Fins for the non-premium, 2015 and newer, GT EcoBoost and V6 Mustangs. In this video we're gonna go over a few different topics when it comes to these diffuser fins. We're gonna talk about the styling, the materials and construction, and the install as well. We'll talk more about the install later, but I can tell you right now that the install for these is easy. It's a one out of three wrenches on the difficulty meter.The MMD Rear Diffuser Fins are gonna be something that you should check out if you're looking for some rear bumper accessories that are going to the change the appearance of the rear of the non-premium S550s, without having to purchase an entirely new rear diffuser. Now there really aren't many options when it comes to the non-premium cars, and if you don't really like the look of the MMD one-piece diffuser these give you another option with a different look. These rear diffuser fins are simply added to your rear diffuser to give it an after-market aggressive appearance. These give you a way to change the looks of the rear end of your car in a very simple, very easy, and also reversible way. That's the beauty of these, in my opinion. They're so simple, yet they do make a difference in looks and you don't have to spend an arm and a leg, or go with an after-market rear diffuser.These have a smooth, matte black finish, so they'll match any paint color right out of the box, and you don't need to change anything or do anything to make them look good on your car. You get two fins for each side of the rear diffuser and, as far as materials, these are made from ABS plastic, which is commonly used for exterior styling because it's lightweight, strong, and durable. Those are all good qualities for an item that's gonna be living on the rear of your car.These are gonna come with everything you need to get them installed. Like I said, a big plus here is that they're very easy to install. They install just with 3M tape that's already on the backside of the extensions, so you don't even have to worry about placing them. They're also gonna come with alcohol wipes and adhesion promoter, so you can make sure you get a good bond and a few pushpins to guide and make sure these stay in place. One thing I did want to mention though is that these are designed to fit the S550 base models. They won't fit the premium cars.When it comes to price you can expect to pay just over the $100 mark for these. Now this is less expensive than the full rear diffuser option, and you still get the change in looks while spending minimal dollars. As far as the install, if you wanna even call it an install, it's very easy. It's a one out of three wrenches on the difficulty meter and you can expect to spend 15 minutes to get these installed. You won't need any tools, but you are gonna want to make sure that you have a clean surface and that you test fit these before installing. Once you have the diffuser clean, use the alcohol pads to prep the diffuser where the 3M will be. Then use the adhesion promoter after you peel the backing off the 3M tape, and allow it to dry. Then it's just a matter of firmly pressing the diffuser fins onto the diffuser after you line up the pushpins using even pressure. I'd just keep in mind allowing these to set on the car before you wash it or take the car in the rain.Wrapping things up here with the MMD Rear Diffuser Fins. These offer a fast and easy way to change the appearance of the rear end of the non-premium S550 Mustangs without having to purchase an entirely new rear diffuser. These give you another option when it comes to exterior styling with a non-premium rear bumper and you can check them out more online right here at

    Aggressive Race Inspired Styling. Do you own a base model 2015-2017 Mustang with the Non-Premium Rear Bumper? Would you like to give it a more aggressive race inspired appearance? If you answered yes to both of these questions you should check out a set of Modern Muscle Design's Rear Diffuser Fins. These MMD Rear Diffuser Fins are a simple and inexpensive way to alter the exterior appearance of your base model Mustang.

    High Quality Construction. Manufactured from an OEM quality injection molded acrylonitrile butadiene styrene (ABS), these MMD Rear Diffuser Fins were designed using the original OEM CAD data from Ford to ensure a perfect fit. ABS is an extremely strong material known for its light-weight, superior durability and impact resistance - making it perfect to withstand the hazards of daily driven vehicles.

    Simple Peel and Stick Installation. No messy glue or drilling is required for installation. These MMD Rear Diffuser Fins are designed to install simply with the pre-applied 3M doubled sided automotive bonding tape. Thoroughly clean the surface and then simply peel the 3M tape from the back of the Fins and set them firmly in place using the included push pins as a guide. It is that easy.

    Application. These Modern Muscle Design Rear Diffuser Fins are designed to fit 2015-2017 V6, EcoBoost and GT Mustangs equipped with the factory Base (Non-Premium) Chassis Packages only (Trim Levels: 050A/051A/100A/300A). Not intended for use on Premium Package models.

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

    Modern Muscle Design

    Fitment: 2015 2016 2017 Details

    MPN# 394110

    CA Residents: WARNING: Cancer and Reproductive Harm -

    What's in the Box
    • (2) Left Hand Fins
    • (2) Right Hand Fins
    • (2) Push Pins
    • (2) Alcohol Wipes
    • (2) Adhesion Promoter Packets
    Installation Info
    Tech Specs
    Will it fit my Mustang?

      Customer Photos (58) Submit Your Photo

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        Questions & Answers (10)

        5 Top Rated Questions

        Do these fit over top of existing Diffuser fins such as the fins on my 2016 Roush Mustang Diffuser to lengthen them?

        • These fins are designed for the base model 15-17 Mustangs only. Unfortunately they will not fit premium or other models.

        Helpful (0)

        Hello, im very interested in the product. What is the reason this will NOT fit a premium bumper?

        • The Premium and Non-Premium Mustangs come with two different diffusers so these MMD Diffuser Fins are only able to be used on the Non-Premium Model.

        Helpful (0)

        In the picture, what are the exhaust cutout inserts? I cannot find them anywhere but on this product page.

        • Unfortunately, we do not carry any exhaust cut out inserts for the rear on the 2015-2017 Mustangs. We apologize.

        Helpful (0)

        At what speed do you think these will fly off and if so is it best to use urethane?

        • These diffuser fins should not at all fly off when they are installed properly and the appropriate time for the adhesive to cure is reached. These fins will still be attached even at highway speeds.

        Helpful (0)

        Can this go on a 2014

        • The MMD Rear Diffuser Fins was designed to fit 2015-2017 V6, EcoBoost and GT Mustangs equipped with the factory Base Chassis Packages only and will not be compatible with your 2014.

        Helpful (0)
        Post Your Question
        5 More Questions
        Sense you guys offer in house painting can I pay to have these painted?? 1 answer
        Hi How Long Are The Fins? Thank You 1 answer
        I've seen customers install these to their premium models and it looks great. Although these were intended for non premium models would they still work for premium? 1 answer
        As far as durability, how are these in a car wash? 1 answer
        Are these an extension onto the small fins already on the car? Also I have a Roush Rear for my current exhaust, will they make for a more aggressive look for Roush body piece? 1 answer

          Customer Reviews (39) Write a Review

          Ratings Summary

          4.6 out of 5 overall rating from 39 customers

          Installation Time: Less than 1 Hour

          • December 28, 2019

            4 2017 GT - Cameron Installation Time: Less than 1 Hour

            Nice, but overpriced

            Took less than 20 minutes to install. They make the car look more aggressive which is nice. But they should not cost more than $40 honestly. $100 is definitely way too much.

            Helpful (0)
          • December 02, 2019

            5 2015 GT - STang Installation Time: Less than 1 Hour

            Easy to install. Look good

            Installed easily. Gave the rear of the car a more aggressive look.

            Helpful (0)
          • September 12, 2019

            5 2016 GT - Kin Installation Time: Afternoon

            Rear diffuser adds nice look

            I have a standard GT without the tail diffuser feature and with this alternate/cheapest way of doing it, actually worked out good. It added aggressiveness look on the rear of my GT. I highly recommend it to cars that have dark color like Metallic green, black and dark gray to stay with the unpainted fins. It it’s not on there, but when you look at in an angle, it looks like one of those European sport cars with diffuser fins.

            Helpful (1)
          • August 24, 2019

            4 2017 GT - 07Stang Installation Time: Less than 1 Hour

            Little mod, big difference!

            These look great! Maybe a little over priced, but not many options for non premium models. Install was easy, I spent most of the time getting them positioned where I liked them. Used painters tape to place them temporarily, then ran strips of tape on either side of the fins so I knew where to prep and place for the final mounting. I spaced them 6 inches apart instead of the 5 inches listed in the instructions. Only gave 4 stars because I think they are a little overpriced, but still worth it IMO.

            Helpful (0)
          • July 23, 2019

            4 2017 GT - Scott347 Installation Time: Less than 1 Hour

            Nice Accent

            Easy way to accent the back end on NON premium models. Pricing is a bit much but overall look and effectiveness overrides that.

            Helpful (0)
          • July 22, 2019

            5 2017 GT - DonP Installation Time: Less than 1 Hour

            MMD product, looks great, fits great.

            Great product, great fit. Subtle upgrade, well worth it. One attaches to the existing bumper securing fitting (existing hole). Get it straight, then use something as a guide to determine the gap to the next one (it catches the bottom of the bumper, height is set, so is easy to line up). I used the instruction sheet (about 4 inches wide) to set the distance. Both sides went well. Lines up and adhesive sticks good (so far). Peel back about 1-2 inches of the tape cover, align and peel the rest of it off, then press. Get the one with the adhesives, not the screws (screw based product does not afix flush to the car, no thanks). Every person who has seen the product likes it, makes the very plain base GT model a little sharper. Looks stock.

            Helpful (1)
          • May 30, 2019

            5 2016 GT - LuisLP


            Simple and clean love it only took about 15mins to install just make sure to have correct spacing in between each one

            Helpful (1)
          • April 26, 2019

            4 2017 GT - BlisteredMunkey Installation Time: Less than 1 Hour

            Easy enough to install.

            Product seems as well made as expected. Install was simple but... I wish they would of been molded together in sets of 2 for easier alignment. Maybe some kind bar between the top and bottom.

            Helpful (0)
          • April 24, 2019

            5 2016 V6 - GP Installation Time: Less than 1 Hour


            We usually do a full rear diffuser on our cars but this Mustang is our daily driver and we wanted something a little easier to install, with less down time and for less money. These MMD rear diffuser fins were pretty easy to install and really look stock! They give the whole car a great new look from behind and look great in the flat black they come in! Overall super happy with this purchase!

            Helpful (1)
          • March 04, 2019

            5 2017 EcoBoost - CarlosC Installation Time: Less than 1 Hour

            Easy quick mod

            Very easy to install! Results look great! Should be cheaper though

            Helpful (0)
          • January 06, 2019

            4 2016 V6 - AshleyC Installation Time: Less than 1 Hour

            Nice addition

            These fins add a great look to the diffuser. I had already painted my diffuser black so the fins ended up matching perfectly. It definitely gives a more aggressive and head-turning look to the car. I agree with other reviews saying they are a bit overpriced, but if they last long then they’ll be worth the price to me. Installation wasn’t too bad. You definitely have to take your time and make sure they’re where you want them. I had some trouble with the two right fins not seeming to lay evenly on my diffuser, causing them to slightly point outward and therefore not match up with the left side fins. It’s not a glaring difference but it caused me to have to pull the fins off and re-adhere them a few times, which was frustrating. Overall I like the look it gives to the car and it’s a great addition to anyone wanting to add some flare to the rear of their mustang.

            Helpful (3)
          • December 15, 2018

            5 2015 V6 - NickP Installation Time: Less than 1 Hour

            Rear diffuser fins

            The fins turned out really nice. The intructions say put the fins 5” apart, I ended up going 6” and still looks great. The install took about 45 min.

            Helpful (4)
          • September 15, 2018

            5 2016 V6 - WilliamB Installation Time: Less than 1 Hour

            Well worth it

            Easy install, a inexpensive mod that makes a big visual difference, $99.00 15 minutes changed the rear to a more aggressive look.

            Helpful (7)
          • September 12, 2018

            5 2017 GT - JordanC

            Make sure they are straight

            Well I didn’t get the premium bumper. The next best thing are these fins but they must be straight or else you know. I put these on my car and I think they look awesome. Take your time and have a spotter before you permenantly set em. Good luck

            Helpful (6)
          • July 14, 2018

            5 2016 GT - PR Installation Time: Less than 1 Hour

            Cool Product

            Looks really nice.My GT is Oxford white so they stand out. Better looking than anticipated and so easy to install. Solid too.

            Helpful (7)
          • June 23, 2018

            5 2017 GT - AbrahamM Installation Time: Less than 1 Hour

            Highly recommend these!!!

            Anyone looking to customize your base Mustang without having to actually modify anything to your car, this is for you. Installation is simple just clean the area good, align, peel and stick. Definitely gives your Stang a touch of aggressive!

            Helpful (7)
          • June 02, 2018

            5 2017 GT - Jacob Installation Time: Less than 1 Hour

            Curb Appeal

            These looks great installed! Kinda hit or miss with alignment and measurement while dealing with curing adhesive promoter and foam tape; so take your time and have patience! Curb appeal is hightened!

            Helpful (7)
          • May 15, 2018

            5 2017 GT - Stang12 Installation Time: Less than 1 Hour

            Transforms the rear of the car

            Easy to a more aggressive look to the base GT not doubt...would highly recommend!

            Helpful (8)
          • May 09, 2018

            5 2016 GT - Hector Installation Time: Less than 1 Hour

            Diffuser fins

            Looks sharp, compliments all the way around. Goes great with a spoiler

            Helpful (8)
          • May 03, 2018

            5 2017 GT - IvanM Installation Time: Less than 1 Hour

            Great product

            Great for the basic mustang gt to give it a good back look

            Helpful (7)

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