moscode 600 " the newest mods"

I have a maxi version 600. I bought it new in the 80's. It's been a very good amp and I still appreciate it's contribution to my system. I notice that George Kaye the original (engineer) designer of the Moscode is now offering some major mods and a rather different approach for his original design. The description and resulting changes to the sound are very alluring. The upgrade package could run into the $1500.00 range. I obviously like George Kaye's ideas on reproduced sound and I'm constantly trying to improve my set up but, it's a lot of bread, so I was hoping some of you may have had some of these modifications carried out and might be able to offer some comment on the results. I would actually appreciate any insight in helping me arrive at a decision.