Also, I've seen people use a cardboard box around the exhaust fan - it will act as a damper (be sure there are no really hot areas). You could maybe use the box it came in. Potted has very good recommendations as well. I used rope for mine. Whatever you don't want to do is use solid hardware to hold things in place, the vibration will carry into your floor joints, etc. You could also use a speed controller, say.. if you have a much larger exhaust fan than you require. Overall I'd save your money and do these cheap effective methods. In combination they can work really well.