I have one of the Nak stasis units and it is very nice despite being an older design now. Get one at a decent price and you can't go too wrong and should be able to resell for what you paid if you don't like it.
I would take an amp designed by Pass over a Krell. The Vandersteen's are very detailed speakers and your old Krell, while well made and very powerful, may not be the best match. I think you would be very happy with the upgrade.
The Nakamichi amps had a reputation in the service industry for being unstable and prone to failure. They were not popular on this account even back when they were being made. They sound OK, but they are not the sort of amp that you want to push hard or abuse.
Nakamichi amps NEVER had a "reputation" for being unstable. They were a Nelson Pass design and well-respected when introduced, and still popular today.
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