fazio

10". I added 3 layers of fiberglass mat. I can stand on top of the box and it doesn't budge.

That looks like a good start there, are you lining the box to stiffen it up Eg milkshake, resin.....

After I molded the box using fleece and resin, I used fiberglass mat to reinforce it from the inside.

The dash speakers are standard 3.5" speakers and can be at least 42mm deep. Just replaced them in my 2015 Journey.

Are you running them off of an amp or the factory radio?

The jack is under the bin. That is why I have handles on the box, to be able to lift it up when I need to access the jack

I am in the process of installing a pair of subs and an amp. I made a custom fiberglass enclosure molded from the storage bin. I will try to post a thread when I am fully done. This is my first fiberglass enclosure.