What used speaker would you buy with $20,000-$35,000 and why?


I'm closer to the 20,000 part, but if I get stretched i would like to know higher recommendations. Remember, this is on the used market - not retail. I'm even interested if you think I should make a huge jump (say to 50,000), but I want to know what justifies that jump. I'd like the best bang for the buck and even the worse bang for the buck. Are there speaker lines that are totally overlooked that sound wonderful in this price range that I need to be exposed to? I may go higher, but lets start there.

PS Let's just assume the upstream equipment is adequate to drive any recommended speaker. We are not limited by upstream components.
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I would purchase a legacy Thiel over the new models.  The new ownership has gone in a direction that is contradictory to Jim Thiel's designs. 
I have liked a few of the older Thiel's, but not all of them.  I forget the models that I enjoyed (we have a local dealer who personally owns them and loves them).  When they were bought out, I personally feel it ruined the company.  JMHO.
What kind of music ? The Big Pure Audio Project  speaker with 4 Neo woofers per side, with Voxativ field coil driver is incredible 
By Any standards. And in the $20k  range 95db efficient 
And you can hear the event well even at low volume .
I know of no other speaker that can match what these will do
At lower volumes,and can rock the house also.many options 
And only 1 capacitor you can change yourself outside the box ,being open baffle totally unique being modular.