speaker upgrade fever

@larseand I'm sorry but I don't have experience with any of the speakers or amps you list.  

In the best scenario, you can demo the speakers you are considering with your amp.  

Also, in rolling tubes, I've sometimes stopped with a tube that I thought sounded great in the midrange, then realized it was lacking bass so I was turning it up higher, which gave the good midrange.  After listening a while it sounded bright so you might look for tubes with more bass to combat brightness.

Best of luck, Jerry

Larseand, seems to me you already have a nice speaker system. If you must change you could try Dynaudio in your price range. The New PS audio Fr5 might be worth a try for less money. There was audiophile on the PS audio forum, that sold his Kef ref 1 after purchasing the Fr5’s. I own them along with 11 other pairs of speaker and so far they are the best bookshelf that I have tried up to this point. 

https://speakerchoices.com/index4.html?pricemin=8000&pricemax=15000

KEFs are on the bright side. However great they are. Almost anything in your price range will sound warmer.

Suggest speakers with beryllium tweeters.  I am very sensitive to sibilance too and a local dealer suggested the tweeters after I had issues with several different speakers over time.  Ended up with Revels and I’m very happy.  Went with the M126Be standmounts since like you I have twin subs and didn't need another set of tower speakers.  There are other manufacturers that use beryllium so you have other choices in your price range.  

Add Sonus Faber to your list. The most musical speakers I have heard.