Thomas, I seem to remember that when the SN2 was launched a UK dealer said that if a hicap were to be added then it had to be a hicap DR. A plain hicap would mean that the DR in the integrated’s existing internal power supply would not be used.
The preamp power supply in the Supernait, like that in the 200, may be DR, but it is a single rail supply squeezed into a box with a load of other electronics. So it has little chance of competing with a dual rail supply in its own dedicated box. So I would be very surprised if a Hicap didn’t perform better than the internal supply as long as it’s properly set up, and in good condition, bearing in mind that a non-DR Hicap is likely to be old enough to need a recap if it hasn’t yet had one.
Another consideration is that not everybody prefers the sound of a Supernait with a Hicap. So in any case you need to listen carefully and decide for yourself.
In answer to your other question, I would take the 82/200 any day in preference to any Supernait. Again, with the usual caveat that it should be properly set up and not in need of a service.
I am just checking out options if I were to return to a “one box system” some day. Well "one box system would still be “a bunch of boxes” I guess… Concidering possibly SN2, record player, streamer, RIAA, PSu’s… I guess I will stick with the HC - 82 - 200!