Lots of information and technical knowledge going over my head here But that's great!
Apparently the MK4s needs a lot of juice therefore the Nbox (Nbox+ better?) with its 4 9V-batteries is recommended? I see some of you mention Church-Audio's preamps, will they do the job just as good?
The Nbox supplies 60V to the capsule (same as the CMC6 body), the Sonosax supllies 48V and the Schoeps VMS021B preamp supplies 60V (I believe).
The CMRs require 9V power which is what the Church Audio preamp supplies. I would imagine that the head of the CMR (what screws onto the capsule) contains electronics which upconverts that 9V into a higher voltage, but I don't think anyone knows. It may be the need for upconversion from 9V that causes decreased sensitivity when compared to the alternatives.
I'm sure the Church Audio sounds great, but in my opinion, no the CMRs are not as good because they provide only 60% of the sensitivity from the same capsule on any other setup. It was the increased total length of the adapter+capsule and decreased sensitiviy that ultimately helped me decide to go with the Nbox.
BTW the Nbox+ is just an Nbox with upgraded (and more expensive) components. Nick can probably tell you more about the difference. There is a listening test that someone posted and the majority of people can not hear a difference between an Nbox and an Nbox+