I've been trying out the small Pioneer 50W subwoofer. I too mounted it to the plastic divider behind the rear seat in the middle. It's not bad, but I'm fighting some resonance in the plastic parts, specifically the long one that it is mounted to. Very convenient being able to have line level inputs (the original subwoofer wires) and powered by the 12V outlet back there. But, IMHO, not worth the effort over the improvements made with the MUSWAY amplifier, which actually get some sound out of the OEM subwoofer, and a lot more low end out of the front door woofers. I might play with it a bit more, but definitely thinking about putting in my JL boxed sub, even though it would take some rear space, or even putting the BOSE sub box back.
I did put down some Dynamat sheets on the back trunk deck while I had the back all opened up. I did not cover the hv access panel, so it remains easy to open if they ever need to get in there for the A/C hv fuse or something else in that rear junction box. Also, put two wide Dynamats strips the long way on the two flat panel sections of each of the front doors, definitely heard some quieting there. My assembly line person on the front passenger side door must have been distracted, because the putty like adhesive was adhered well to the moisture barrier, and almost not at all to the metal of the door. The bead was also off in a couple of places. It made it easy to remove that side, and between a roller and my thumbs, I got it tacked down now to the metal of the door when I reinstalled it. Fortunately that tacky putty like bead for the plastic moisture barrier remains pliable, and with just a little care, goes back on like new.
I did put down some Dynamat sheets on the back trunk deck while I had the back all opened up. I did not cover the hv access panel, so it remains easy to open if they ever need to get in there for the A/C hv fuse or something else in that rear junction box. Also, put two wide Dynamats strips the long way on the two flat panel sections of each of the front doors, definitely heard some quieting there. My assembly line person on the front passenger side door must have been distracted, because the putty like adhesive was adhered well to the moisture barrier, and almost not at all to the metal of the door. The bead was also off in a couple of places. It made it easy to remove that side, and between a roller and my thumbs, I got it tacked down now to the metal of the door when I reinstalled it. Fortunately that tacky putty like bead for the plastic moisture barrier remains pliable, and with just a little care, goes back on like new.