I have an "upgraded" PSU sitting on a shelf which I bought from another HH:er. Neither of us have tried it yet though.
I'd be very interested in trying a better PSU. I read the 'Circles threads about upgrading PSUs before joining here, and its been on my radar since. Amplifiers are often described as amplitude modulated power supplies, and in general what comes out of a PSU tends to go straight through clocks, DACs and amps.
By coincidence I happen to have an 861V2 and a G68J at the moment, so I whipped to tops off last night. I believe my 861 had the PSU upgraded, and it looked identical to the G68 PSU, but also has a secondary supply board feeds the motherboard. The secondary board is quite large, and full of regs and caps. I assume it improves regulation, ripple and noise over the primary supply. The G68 seems to have some regulation on the motherboard, but it`s much more basic.
This suggests that M have addressed the need for clean power with the 861, as you`d hope with an expensive processor. My first thought was that maybe the 861 could be further improved with a better supply, but that might be wishful thinking. Second, there may be more scope to improve the G68 with a better supply. I`m sure there`s much more to the 861 than the PSU, but I like the thought of a modified G68 that closes the gap on the 861.
Nick