Heck, I just traced the vent outline, cut out some 1/2" birch plywood, lined up the holes from the vent on the plywood, cut it out to fit over the vent, traced the outline of my 6x9 speakers, and mounted them in the vent holes. I also put some heavy plastic to keep the weather out as best as I could. Seems to work pretty well so far at least until I can finish the "real wood" to replace the plywood. Now back to getting a serious mount for the cd player in my glovebox....
Hope it helps. It only cost me about 4 bucks to make and a little time with my trusty jigsaw. Cheers.
