Our does the shakes, mostly when loaded with several heavy towels. As Dan pointed out, shortening the distance the front legs travel will help, and the foam helps a little. I would try putting the foam between the washer and the side walls, not between the top and bottom of the washer and dryer. Based on discussions with many other W/D owners, you're going to get some vibrations. The spin cycle produces a lot of physical forces going on right at the very front of the RV. The physics involved suggest it will be difficult to eliminate the vibrations. The best we can do is minimize them.