My system is posted for all to see. I bought some aftermarket feet from Galen Carol that bolt to the bottom of your speakers and give them a wider stance for stability and with adjustable spikes so that you can level them perfectly. They made a very big positive difference. I think they were less than $250 for all four pieces.
Galen Carol is a Stillpoints dealer. do you think they would give you an honest answer about what you might expect with Ultra SS compared to what you have? It's probably worth asking, and there's always that money-back satisfaction guarantee