If you need to seperate your sub from the floor, I can't recommend the Auralex GRAMMA strongly enough. For only $50, you will be amazed at the difference in the sound. Of course, it does add a small platform to your room which probably would not go well with the WAF. But part of it is purple!!

If you need more options on speaker damping material, you can check out this site:
www.partsexpress.com