The pallet thingy is a
Subdude, which is made to isolate the vibration of the sub from the floor....
I would be putting something under there as well, I have some spongy looking pads under my Plus/2's in my great room, as uncoupled they seriously shake things in my kitchen as well as pipes in the walls in my bathroom and other stuff.
You are going to love that sub....
I have been contemplating getting a pair for my Great Room to replace the Plus/2's.