Does highend heavy amps needs ampstands?

putting it on spikes (tiptoes) with protective discs for the floor should do a good job. If your amp weighs over 50 pounds that should do enough. A block of granite or other stone or concrete would be good too. A stand if you are loaded with $$$.
Yes the amp should be isolated from the vibratioal feedback of the floor. a lot of electronic parts can have effects from being vibrated, the biggest is tubes, but caps and other stuff can add grung to the sound from being vibrated.

Elizabeth, have you anything to back up your assertions about the ill effects of vibration on solid state circuitry or are you repeating something someone repeated to you because that person had heard it also repeated. I think I am being repetitious, you get my drift.

All amps especially powerfull ones do have a vibrations and you can't kill it whether you're going to use granite or marble stand.
Elevating the amps will add an extra room for heat sinks. I have my amps on my journal table since I needn't any journal table now and it kind-of convenient to access to the binding posts, mut switches etc.

Experience.
My little amp, a Forte' 4a has better sound when I dampened the external heatsink fins. High frequency information was cleaner, more precise. I use chunks of rubber bottle stoppers cut into thinner strips, staggered across the fins. This was also mentioned in some article I read about MY AMP, later.
Yes, it is difficult to know if someone is just making stuff up, if they are an expert in the field, if they have actually experienced the phenomena, if they are just totally looney anyway, if they have studied it with an open mind, if they have studied it with extreme bias blinding them to anything but what they are certain has to be, because that is what makes sense to them....

I've experienced significant improvement through the use of resonance control – equipment feet and amp stands!
Years back I put my Threshold SA-4e on a Sicomin plate. That was a big step ahead - cleaner sound, improved bass and dynamics. Later I bought a Copulare stand (www.copulare.com) and reached a significant higher level of improvement for the SA-4e and the Krell FPB 300 which replaced the Threshold.
Today I have a wonderful Chord SPM 5000 power amp. Although I already use the Copulare Aural amp stand I got further improvement replacing the standard equipment feet with Millennium Audio M-Pucks. Later I ordered a special integrated resonance control for this amp, called Chord Integra System instead of the M-pucks. Again another level of improvement. I tried to use the excellent Integra System to place the Chord directly on the floor, without the Copulare stand. It was immediately obvious that the crystal clear sound suffered. So I placed the Chord with the Integra System on my Copulare stand. The combination of both methods of resonance control gives best results.
So – yes, excellent resonance control will definitely improve your amps performance. I think the amps suffer from vibrations that they primarily produce themselves and secondarily pick from the environment. My amps are solid state and the Chord even uses light weight switching power supplys. Nevertheless they all are as sensitive as you would expect from tube gear.

Elizabeth,
Finally!

Sistrum platforms/racks are just the thing for big ass amps. Little ass too. Go on their website:audiopoints.com for the deal. Speak to Robert. He be da man over there. If you've never coupled, you're in for a real treat. peace, warren

I heartily second Warren's suggestion as to the Sistrum platforms/racks. I got amazing results with these in my system. By far the best isolation devices I've tried (and believe me I've tried a few).

My Forté 4A also responds very well to energy draining and damping. I use three Goldmund cones under and they have eased and relaxed musical presentation and HF response. Used hockey pucks under the cones (25 cents each) also helped with focus. I plan to use Dynamat Extreme under the top plate. I would not like to place anything in the fins that could interfere with heat dissipation, though...