I made it so the passenger box ends right where the bottom of the panel Malibu puts in there is, I don't have a heater but could fit one on top of the box if i wanted it. The sub weighs 40 pounds and with the box i know it is close to a 100 so i did not want to mount it up above, but with the right sub selection (no monsters like i chose) and a lighter box (all fiberglass would be nice) it would work great.
For the passenger side I made the box so the back follows the same angle as the hull of the box, the edge ends right where the opening for the seat is, so if i want i can fit a slalom ski in there between the box and the battery. I have yet to find a highoutput alternator that fits a malibu (they use a really small model on the new motors) so I may add a second battery as well, and if so am pretty sure I can fit it in front of the sub box so i can still fit a ski in there.
If the plexi doesn't work, go to
www.go2pac.com, i am pretty sure they have a infared extender that will work.
You can fit a lot in there if you are willing to customize and give up space, I don't need room for boards since i have racks so i decided i could afford it, but i wanted some storage and since i wanted loud bass i went with a high powered monster. I do the installs at a marina so i have seen a lot of mistakes ( i had to fix some) where peole picked the wrong equipment and got mad beacuse their boat had speakers everywhere but was not as loud... Just like a car, the install is more important than anything.