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JL Audio Stealthbox Subwoofer Upgrade Kit (15-19 Fastback)

Market Price $918.99 You Save 8% ($69.99)
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$849.00 (each)

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  • Item 393861

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    Features, Video & Details

    • Upgrade for Mustang Audio
    • Replaces Stock Subwoofer (If Fitted)
    • Provides Huge Extra Bass
    • Sealed Enclosure
    • Handles Up to 400W
    • Easy Installation
    • Two-Year JL Audio Limited Warranty
    • Fits All 2015–2019 Ford Fastback Mustangs

    Review & Installation Video

    Review & Install Video

    Give Your Stang Some Serious Bass. If you’re not feeling it from your Fastback Mustang’s stock audio system, it may be time to invest in some serious bass power. The JL Audio Stealthbox is a sealed enclosure design that simply fits in the location normally used by the optional Ford factory subwoofer. The built-in 12 inch subwoofer driver handles up to 400W, pumping out powerful, deep bass.

    All Fiberglass Construction. The Stealthbox is built from rugged, sturdy fiberglass, creating a sealed enclosure that is tuned to work in your Mustang. The front face is finished in a hard-wearing fabric that fits right into the trunk of your car. The enclosed 12 inch subwoofer driver features a cast alloy frame, rugged polyropylene cone, and long-lasting rubber surround.

    Installs Easily. The Stealthbox simply fits into the same place in your Mustang as the optional factory subwoofer. No drilling or cutting is needed. Any factory subwoofer must be removed.

    Two-Year Limited Warranty. JL Audio provides a limited two-year warranty on the Stealthbox.

    Application. The JL Audio Stealthbox Subwoofer Upgrade Kit fits all 2015 to 2019 Ford Mustang Fastback models.

    Technical Note. If you have a Mustang that was not equipped with a factory subwoofer, you will need additional speaker wire to install the Stealthbox properly.

    Fitment: 2015 2016 2017 2018 2019 Details

    CA Residents: WARNING: Cancer and Reproductive Harm -

    What's in the Box
    • (1) Stealthbox
    • Installation Hardware
    Installation Info
    Will it fit my Mustang?

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    Questions & Answers (6)

    5 Top Rated Questions

    if you don't have the factory sub in the car already, will this still work? or is it only to upgrade the existing one.

    • This Stealthbox Subwoofer Upgrade Kit is a replacement unit however it can be installed into a vehicle that does not have a factor subwoofer with a little wiring.

    Helpful (5)

    According to my local Ford dealer the factory sub box is the same part number for the fastback and the convertible. Why won't this one work for a convertible if the factory box is the same for both?

    • The enclosure used for the JL Audio Stealthbox Subwoofer Upgrade Kit is larger than the OEM sub enclosure and will not fit into the convertible's trunk properly due to clearance issues.

    Helpful (0)

    Is it true plug and play if you have a factory sub? Same connection and all?

    • The JL Audio Stealthbox Subwoofer Upgrade Kit is a true Plug-And-Play Unit if your Mustang was equipped with the factory subwoofer. If the vehicle was not equipped with the factory subwoofer, you will need to modify the wiring.

    Helpful (0)

    Is it possible to to have two left and right ? Or it only comes for the right side ?

    • The Stealthbox Subwoofer Upgrade Kit is an upgrade for the factory subwoofer. It is not available in a Driver's side configuration.

    Helpful (0)

    Why will this not fit the Convertible? Is there an option available for the convertible or can this one be modified to fit?

    • The subwoofer upgrade kit is designed for 15-18 Mustang fastback models and will not fit the convertible model. Unfortunately at this time, we only offer an upgrade kit for the fastback models.

    Helpful (0)
    Post Your Question
    1 More Question
    Is there a built in AMP? 1 answer

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    Customer Reviews (4) Write a Review

    Overall Rating 5

    out of 5 stars

    • 5/5

      June 26, 2018

      Great sound and fit

      amazing sound from this unit. complete factory look and still have space in the trunk!


      Year: 2018 Submodel: GT

      Helpful (6)

    • 5/5

      June 13, 2018


      Great product and service. The product fits perfectly in the mustang.


      Year: 2018 Submodel: GT

      Helpful (5)

    • 5/5

      May 29, 2018

      Boom Boom Boom

      JL Audio delivers again and again. It's not too much bass but enough to give you that car rattle if you want it. Nice compact deep full sound. Be sure to pair a good amp with it.


      Year: 2016 Submodel: GT

      Helpful (5)

    • 5/5

      April 26, 2018

      Great Sub!

      I love this sub and I love the fact that it opens up my trunk space. the only issue i've had with it is the speaker grill will vibrate loose and fall off and I have to keep putting it back on. I'll look to see if i can find a better way to secure it. But Overall It sounds great and fits perfectly I'd definitely recommend it to anyone looking to add some bass to their mustang. Also I'm using the factory stereo which I upgraded to sync 3 myself and an Alpine mon amp to power it.


      Year: 2015 Submodel: GT

      Helpful (10)