Current Sotas do not bounce around as the spring system is better controlled. The Sota Cosmos uses a different motor which is mounted on the solid aluminum plinth and therefore suspended, so those issues of unsprung motor/sprung platter are eliminated, but truthfully, with the later suspension, there was little movement even when changing records. The Oracle Delphi V and VI are like that too, compared to the early models which were much more affected by movement. The suspended table manufacturers have fine tuned their suspension systems after learning that you dont have to be as delicate in your suspension system to get the desired isolation. The Sota Cosmos motor is also designed with minimal vibration, enough so that I cant tell when its running by feel or by ear.
the old outboard power supply has nothing to do with the above issues, which in my opinion are a non issue anyway. None of my Sotas have exibited sideways movement during play after initial startup anyway, and watching the tonearm during play doesnt reveal any side to side motion that isnt caused by an eccentric record spindle hole.
I have also never had an issue with tonearm weight being a problem, from SME 309 to Helius Omega, both substantial arms. These suspension systems are designed to filter out vibrations around the 2hz level, with other means of dealing with higher frequency vibrations.