Full Range under $5k-ish

As most know, I am a Vandersteen fan. 
And, you might ask, why so many have recommended them?
Because they outperform for their price range, and are very listenable. 
But, that is your choice. All I and the other posters want is to guide you to something that we think would be a good move from your current speakers.

For under $5K, you could get a pair of 3a sigs with a pair of 2w/wq subs and be pretty close to a Quatro.
A more attractive option would be to get the Treo's plus subs, but that is probably a bit more than your budget.
Either way, you would get a full range speaker system.
If you let us know your location, maybe we can direct you to a dealer.
Bob

+1 on the goldenear technologies, esp if you have some loyalty to ded tech. Sandy Gross is a founder of both.

Having heard them recently, taking up less than I sq. ft. of space and only 40 inches high, these ATC SCM 40 V2 are among the top of your price class.  The ATC speakers are used in more mastering studios than any other for a reason--very dynamic, punchy bass, with extremely fleshed out and detailed midrange and highs that are airy and extended yet don’t call attention to themselves. They need plenty of good power and sound best away from the front wall a good 5-6 feet. They have a good soundstage when positioned properly. They have curved and very solid cabinets as they weigh 75 lbs. each. They look nice and the drivers are very rugged and should last a LONG time. The V2’s should be able to find used for around $4000-4300 in excellent shape. One can stand or sit and the highs are still there, not much change in sound between the two positions. They have no weaknesses. I own Vapor Audio Joule Black speakers with a few upgrades which are simply awesome sounding speakers, but if I didn’t or I wanted to downsize without a big drop-off in sound, the 40’s definitely would float my boat.
You should at least hear them somewhere.

Bob

Be brave and get a pair of the D&S Tech Labs FM2's, around $5,000.00 and they will satisfy you for years until you upgrade to the FM4's.If you are in the Chicago area you can come over and listen for yourself.Great speakers that no one has heard of, and no they are not HT only speakers, the bass is awesome and can handle whatever power amp you can throw at them.

https://libertyaudio.com/service/x-vox-loudspeaker-system/

From its maker

Good Listening

Peter