buy sub with triple magnet sure box wont move one, hehe....somore use 1" mdf haha heavy kaw kaw....
some use velcro, some use nylon strap, but best is screw the box to the floor permanently, confirm wont move one, haha...
i had mine bolted to the chassis last time, can feel low bass rumble thru your seat, just from a 10" sub, hehe....