And here it is finished. After my last pics, I carpeted the whole box, and put in the speaker connectors. At first I tried using velcro on the bottom, the idea being that I could remove the boxes in a pinch. I also liked this idea, because I could put 40 extra feet of wire to each box, and when I'm camping, I could have just put the two boxes around the fire and have music. BUT, the velcro failed to hold onto the stock carpet. So instead I opted to cable tie the boxes to the carpet. This way, they're still relatively easy to remove, and I have no worries that they'll fall off.