So in searching for a noise and cleaning the dirt out from under the rear interior, I noticed a bracket that has nothing in it under the driver's side rear passenger seat. The amplifier and satellite receiver are both in the rear quarter panels so I can't guess what goes here.
Interestingly, the passenger's side carpet and sound pad have cutouts for another bracket the same size, but there's nothing there.
Other WK owners with more options than me, whatya got?
PS- I also seem to be retarded WRT getting photos to show up. May have to right-click+open image in new tab