"Absolute best" used speaker for $8-10K

My current amps is Krell 350MCX, Ayre K-5XE with a Esoteric DV-50S.
Planning to get a pair of Pass Labs X600.5 along with an McIntosh C200 pre. and the ayre C5-XE.
Cable is AZ Silver Ref. II and Hologram II but plan on upgrading once the speaker choice materialize.

A few recommendations (very nice system, by the way):

Zu Definitions. How can you turn down a 60-day trial?
Tyler Woodmeres. Used or demo (call Ty) will be in your budget, and they will fill that room.
Silverline Bolero. Made for the music you like, and work well with Pass amps. Refined, resolving, they sound 'right'.
EgglestonWorks Andra II. Maybe $500 over your budget, amazing speakers.

Best of luck.

Boa2, I'm contemplating on the Andra II. From the Stereophile review it look like one of those rare one that does everthing just right.
Any could share some info. on this speaker with me. Thanks again.

Andra's can be difficult to place, but sound amazing when positioned well.

Ny suggestion would be Legacy Whispers. Very open, revealing and true to the source. A "you are there" speaker, if that is important to you.