I tried Ingress rollerblocks under my Grange and heard some nice sonic improvements.
From what I understand they are similar to Symposium rollerblocks but at a fraction of the price. I might try them also under the Supra power supply unit.
There are few forums mentioning the Ingress products as well.
https://audiotwo.com/products/ingress-audio-level-2-stainless-vibration-isolation-system