Originally posted by Brentos:
Did you cut any sheet metal in the deck or were you able to use the existing hole?
I used the existing hole (no cutting at present). I bottom-mounted the sub to a piece of 3/4" plywood that I cut to mount on the bottom of the rear deck. This gives the sub pleanty of room for excursion, so it doesn't thump into anything.
I also dynamated the top of the plywood and the bottom of the rear deck. I'm not sure if it helps out at all, but I had some lying around in the garage and decided to put it to use.