So here is a tip, specifically for you. I went on a road trip this weekend and when I was packing I threw a big thick blanket and a pillow under the time floor board, like on top of the spare wheel. That cut out a lot of the drone, sound deadening the trunk definitely helped with the booming that echoes above the spare tire. Right now I've got an old comforter under there acting as a sort of poor man's sound deadening. It doesn't eliminate the drone, but it helps, and it cuts the booming wayy down. Give it a try and let me know if I'm just blatantly lying or not, but I think it definitely helps.