What isolation feet under your amp with great result?

three easy payments, I believe that ebm is describing to use the Critical Mass Center Stage as footers under the amp and, thus, between the amp and the Ultra Stealth platform.  That is the same method that I had described in the page 1 of this thread except I use the same brand (Symposium Acoustics) Rollerblock Jr + footers.  They are less expensive than the Center Stage footers and, IMO, provide excellent vibration drainage from the amp and directly into the Ultra platform.  You can contact Symposium Acoustics directly, speak with Peter (the owner) and he will provide excellent information and help to you.
Good luck.  Be safe and be healthy.  

For fun, I just ordered some springs yesterday.  I tried to go with something shallow enough so my amps wouldn't look weird and something wide enough for stability.  Regarding the spring constant, I ordered springs where the total weight per spring would be just a touch over one-half the spring's maximum capacity. 

I used some empty cat food cans under an amp the other day to raise it up and it sounded quite good. Can't really say if it helped or not.

Another vote for AV Room Service EVPs.

If it ain’t broke, don’t fix it.
After reading this thread I tried some footers under the amp.  Deteriorated the sound.  Removed them.
Happy camper!