I have a 2-door but bought the 4-door version of this kit a long time ago, as there was no ETA on the official 2-door compatible version. Some others had done the same and reported that it fit "well enough" with the upper metal bracket just being a little off-fit.
Did the official solution for...
I just swapped the factory sub on mine this weekend (B&O -> Polk 8" MM1 DVC).
The Sub: https://www.amazon.com/dp/B073JWTS1T
The wiring plug-n-play adapter: https://www.amazon.com/dp/B0007WTEVM
^Note that for the bronco the black and white wires of the adapter are effectively reversed - so ignore...
Ding Ding Ding! Dead-on, found it within seconds when i took the flashlight under the first well. I would not have figured this out myself probably until summer.
Your prize is 2 beers at your choice of venue if you're ever in central NC, no expiration date.
If you're talking about the ones built-in to the floor carpet, this piece is actually significantly smaller than those. I appreciate ya throwing an idea out there though!
Those are probably in several places but your most likely candidate is the wheel wells - they're used in all four to hold the outer plastic/felt guards to the body. I got to play with mine during a mudflap install. Might want to check for a missing one!
Or, for a story that doesn't have to...
Here's the context: Found this little fella on the carpet back by the tailgate a couple days after I picked the Bronco back up from a PPF/Tint shop. Definitely wasn't there before because I had thoroughly detailed everything prior and would have found it then. Showed it to the shop already...
You must be the guy the folks at Crossroads mentioned when I was chatting them up a couple weeks ago about preparing for mine to arrive. I mentioned i was quoting around for PPF and you came up. Small world?
There was a post recently where multiple people had random power loss issues that traced back to a loose battery terminal connection from the factory. There's no excuse for that to have been missed several times by your dealership, but...
You may also just have a cursed battery. Apparently this...