Ken Kessler reviewed the DS optical cartridge( Grand Master?) and the Soundsmith Strain Gauge in Hi Fi News magazine, this year. Basically he said they are both on a level and both game changers.
Sure they are game changers - 52000EU for the cartridge and equaliser - they are going to destroy the market for sure, sell a million units before the. years out.
No, the only reason they could be called game changers is the definition of conspicuous consumption - I’m waiting for the first $100k cartridge. $50k cartridges have been around for some time now - its a bit meh.