Speaker upgrade for classical music

If you have $4 - $5 grand to spend, with your electronics and desire for classical music and midrange, you really need to consider Sonus faber Sonetto V’s at $4,999.00. Quintessence Audio in Chicago is a great dealer with good demo capabilities and knowledgeable staff. They may even have a demo pair at less money. The Sonetto’s are easily matched with amps both SS and Tube. I have owned Luxman, and Rogue Audio amps and Focal, B&W, Yamaha NS 1000, and finally Sonus Faber Venere 2.5 and now Sonetto V speakers. While I don’t have a $100k system, mine is a $15k system. I’ve had friends with $70k systems say they can’t get the sound that I have. I can only agree that Dynaudio, Monitor Audio and the many other suggestions you’ve received are good speakers, but you’d be selling yourself short if you don’t at least audition the Sonetto V’s. Good listening and good luck!

I've never liked Polk Audio loudspeakers.  Big cabinets stuffed to the gills with cheap drivers and sold for cheap.   They look good, but...

Your very best value is in a good DIY loudspeaker project, or possibly finding a well-made DIY set used.  Don't turn your nose up at DIY.   Many of the designs are done by the best audio engineers on the planet and are just as good as the best commercial designs.  Within your $8k budget, you could easily put together the Linkwitz LX521 system and never want another speaker again for the rest of your life.  Will stand up against the top line $100k MBL system.  

The LX521, properly done, has no need for sub-woofers.  This is a project you could readily afford.  They do come up on the used market from time to time, but they're so good that few have a need to part with them.   The primary drawback with the LX521 is that it uses an active crossover and multiple power amps, so it's a considerably more complex project, but many have built them and you WILL be the envy of every audiophile visitor.

Another DIY project is the SEAS Thor.  Total materials cost will run you about $2500.  If you don't want to build it, Madisound partners with a cabinet maker that will make it up for you and ship it to you.  Delivered will probably run you about $3500.

The Thor was designed by Joe D'Appolito, one of the best known loudspeaker designers on the planet.  This is not some cheap throw together.   This is true audiophile hi-end.  This design is very comparable to the Joseph Audio Perspective 2 Graphene, which retails at about $13,000.  Both designs use the same tweeter and have transmission line cabinets.  The Thor uses a slightly larger bass driver.

I own the old magneplanar IIIa for 33 years. Insuperable for classic and jazz music.

You should be considering a three way floor standing speaker of some type if you are playing classical music. I still have in storage a pair of Focal Electra Be speakers I used to have in my
TV and listening room in my last home. I had a larger listening room; a little larger than yours -and with a 200 Watt McIntosh amp driving them I was able to enjoy pretty much the entire sound spectrum. 
    By the way, I live in the Phoenix area and could even set up the speakers if you were interested in listening to them. I am planning to see the Focals later this month, so you could have first listen to them. 

Second the Sonus Faber recommendation.  (They also look great, if that is a consideration in your family.)