I'll probably get slammed for being a audio delusional-ist, but I found the spikes do help on carpet. Tightened up the bass. Of course, that could have been the result of the levitating wires, but I thought those primarily helped on the mid range octaphonicals.

Panny 3000 PJ, 118" Carada, Denon 3300, PS3, Axiom QS8, PSB 5T, B&W sub, levitating speaker wire