Hey Rick,
You've nailed the intent - rubber feet for floors, spikes for carpet. I am using the spikes, and like not only the fact that the spikes "couple" the speakers to the mass of the floor, but also that nobody else in the house can slide them out of position
There is probably some sonic advantage, but I don't know if I could hear it. Be pretty sure where you want them before you put the spikes in, because you have to be thoughtful and deliberate about tweaking the placement after that.
I think Axiom might send you a modest Thank You gift for successfully closing the deal on a new sale if they can verify the particulars.
