Amps under $5500 new or used

Ok hopefully this won’t start a flame war... lol... First my system I am rebuilding after many years.
Adcom GFA-565 monoblocks Musical Concepts Elite and Older Mini Platnium mods (Selling)
AVA Fet Valve CFR w/phono (most current version)
Bel Canto Dac 3 (Will upgrade 2019)
Vandersteeen 2ce sig ii ( Probably Upgrade to the 3a 2020)

So this year I am upgrading my amps. I have a set of Quicksilver M60’s with 6550’s that I am pretty impressed with. Been told that the Mono 120’s with KT 150 huge improvement. Anyway what other amps are worth looking at. Here are some I have thought about.
Quicksilver Mono 120’ or V 4’s ( new or used been told at this price they are hard to beat)
Atmasphere M60 (used obviously in my price range, heard them and they are very nice)
Audio Research Ref 75 or 110 (used downside blown Tube equals service. Although I am close to the Twin Cities. Have Auditioned them and like them) 
Mcintosh MC275 (although not a Mac Fan. But have heard this is a nice amp would monoblock down the road)

So any others I should Audition?