Best speakers in the 3000 -5000 range

I bought (and sold) a pair of the original revel studios for $4000. You'll be hard pressed to find anything better for that price used.

I like my PSB Golds, but I have found most PSBs to perform well above their price point. Their best is the Synchrony One.

OP, can you explain what it is you are looking for your speakers to do differently? What kind of sonic change are you looking for? What would an "upgrade" mean to you? Absent that, we can only recommend "good" speakers in your price range, but we are looking for different things, for example I am much more concerned with midrange accuracy in timbre, and would sacrifice ultimate bass for that, which is why I own Merlins, they provide the kind of sound that appeals to me. Have you heard any speakers that you liked better than what you have, and if so, in what way? Maggies and Harbeth are very fine speakers, but they may not be doing what you are looking for, where a Vandersteen 3A might very well do. IOW, more info please.

I agree with Edorr that the original Revel Studios are a very good speaker, and a good choice in this price range. (I sold mine for $4,400, so they are in your price range.)

They have a very well extended treble response, and there are front and back tweeters, which have controls to adjust the level, in case you want more or less treble response. (FYI: The treble response, while very well extended, is not quite as refined as my current speakers, (the EgglestonWorks Andra II speakers, which have the renowned Dynaudio Isotar tweeters). But the Andra II speakers cost double what the Studios do, and it took a side by side comparision to hear the difference.)

The mid-range is excellent and very musical.

The bass response is deep and very quick. (They have really quick bass response, and no trace of boominess at all, IMHO, which is one of their strengths.) They are not quite a full range speaker though, as they don't quite go down to 20 Hz, but they do get pretty close.

They have very good imaging and soundstaging. The build quality is very good as well. For the price, used of course, they are highly recommended.

(However, I do understand that aesthetically, they are not everyone's cup of tea. However, both my wife and I both appreciated their contemporary looks, and they looked just fine in our fairly modern decorated living room.)

My two cents worth.
Good Luck in your search.

I love my Focal Chorus 836v speakers that are right at the extreme bottom end of your range. See what you think.