Just to let you know the effect a powerful sub could have on that drywall.... I'm not an overly loud listener and have my sub tuned to match my speakers so it's not cranked by any means. However, in a good movie scene like the depth charges in U-571 and many others, my drywall can and does shake, even on the far side of the room.

It's not detaching from the studs or anything but you can feel it if you are leaning on it and on the far side of the room, the adjoining room is unfinished and I can't leave anything leaning against the inside of the drywall or I will hear it resonate. I also have to slightly open the door to the closet under the stairs and the adjoining room or they vibrate in the casings.

A good sub is a powerful device. Don't hide it away in drywall paneling as it will likely reduce the sound quality a good bit and just might shorten the life of the panels. ;\)
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With great power comes Awesome irresponsibility.