Floorstanding speaker experiences/recommendations in the $12-25k range

Agree with those suggesting subs before dropping $15-$20k on new floor standers.  A well integrated sub that goes to 20Hz sounds like the ticket and much cheaper.  If it turns out not to work for you sell the subs and move on to a floor stander.  

Hello, I have a couple recommendations:

Tekton Encore or maybe even the new ones- 1812 overture? $21k

I like this because they are new. 

Sonner speakers win a lot of Best Room at audio shows

If you truly love your your speakers in your room then try a pair of Rel subs  

If the RELs take up to much room for the frequency and you want to really blend your subs in then go with the JL Audio F110 or F112 subs with the JL Audio CR1 crossover. You will need an identical interconnect that you are using on your amp. 
this will seamlessly blend your speakers to your subs using analog not digital. This is what I and friend use right now with out full range speakers. It’s really amazing. $11k to $13k plus matching interconnect. 
 

Last is the Revel Salon 2s speakers. I believe these go down to 25 hz. They don’t take up a huge foot print and even have built in crossover controls on the back. They are a four way design with two different mid drivers and beryllium tweeters that are smooth as butter. Knew they are $24k. Used is around $10k-13k. They like power so a good amp is recommended. 
 

I hope this gave you some good ideas. 

I was pretty impressed by Apertura Edena speakers.

https://www.6moons.com/audioreviews2/apertura/1.html

You are absolutely correct in considering the Borresen X-3's....They are a $25K speaker you can buy for $11K....I spent 3 hrs. last night in total amazement. They make old cd's that I haven't listened to in years, alive and exciting. Details I never knew existed in the music come thru and you'll hear the songs presented like never before.There are a lot of good recommendations here...I can tell you the X-3's will be your last speaker purchase. ps. don't let anyone tell you that the bass is weak....It's deep and punchy and rock solid. My next door neighbor even commented on my music.

I was shopping for speakers in this price range last year. I listened to the Sabrina X, Magico and Von Schweikert, which were all technically very impressive.  I also listen to a lot of jazz and I ended up getting the Devore O96's, because tone is very important to me, and I loved the sound of sax, drums, piano and bass through those speakers. I also listened to the Gibbon, but they are more of a hi-fi sounding speaker. The O96's are also good all around for rock, folk, classical.  They don't excel in deep bass, but with 10" drivers, for me they go deep enough to satisfy. If you appreciate the kind of tone they can produce, they are worth auditioning.  I was also very impressed by the depth and layering of the Magicos, which sounded more natural to me than the other choices.