Maybe they tell you to solid mount them,knowingthat they will fail sooner and you'll buy another one. I don't know why anyone would mount an electonics device solid.The components maybe encapsulated in epoxy, but over time these vibrations coulddamage relays, both electromechanical and reed and the plates inside capactors. I thought about going with a Pro 2, but then I got to thinking, my dyna 4000 has been working great for approx 9 years, why change it? And it's rubber mounted.