Hi Jeff; I am considering either building or buying spiked amp stands for my 90 lb. DNA2s. BUT, I happened to be on the 'phone with John Dunlavy, of DAL Speakers, recently, and he is not universally impressed with spiking everything.
In fact, it's my understanding, that NONE of his speakers are spiked-- the $6K Alethas are not. He flatly stated "they don't measure better when spiked". The reason being is that most houses have wood floors with joists, crawl space, basement etc, and he says "why let your speakers or components vibrate with the floor".
His preference is to let the speakers or components "float", especially on carpet. Well, what he had to say made some serious sense, and I'm still thinking about it. My conclusion so far is as usual-- you just have to try it and see, and that it probably depends on specific conditions.
Spikes are certainly worthwhile in many situations, but not all. I know this is probably not much help, except for giving you something to think about. J. Dunlavy has had a tremendous amount of audio experience, and is one of the "heavy weights" in the audio field. It may be that either floating or isolating the amp is better than spiking (coupling) to the floor. It may also be that there is no sonic difference. Cheers. Craig.