A friend of mine went from the Thiels to the Avalon Eidolon. He has had them for several years now, and is very happy with them. These require a fair amount of power, however, your Pass 600 should do nicely. (He has successfully used a Classe CA-401 (400wpc) and VTL 450s. He is now trying Rowland 501s.
These cost slightly more than $20k new, (I believe $22K), but not much more.
Good Luck in your search.
These cost slightly more than $20k new, (I believe $22K), but not much more.
Good Luck in your search.