The 800 Diamond is so heavy and stable that I initially left it with the steel ball rollers on the carpet (suspended chipboard floor).
I then replaced the rollers with StillPoints Ultra Fives which improved mid-range quality and micro-dynamics. No significant change to bass quality.
Unlike the 803 Diamond, I didn’t need to use a platform with spikes for stability due to the huge 800 speaker base!
Again my experience is that optimal positioning of the speakers is more important than any isolation.