Mini Monitors under $500 used


I have a small room 10x10x8 that Im using as a den. Have a Nad 326bee and Marantz 6250 cd, what would you recommend for speakers? Detail, sound stage, and resolution are important to me.
thank you for answering
Brian
brianvportugal
ACI Sapphire III or Anniversary if you can find a good deal. I thought my old Sonus Faber Concertinos sounded good but the Sapphire III were much better.
Right now the Airmotiv monitors are on sale. You can get the Airmotiv4 or Airmotiv5 for under $500 and they have built-in biamplification. This is a high-tech composite slot-loaded woofer with a Heil-type folded ribbon tweeter.

There is also a pair of Quad 11 L2's on A-gon for $450/pair. I have no affiliation with the sale or seller. Those little Quads are fabulous and relentlessly engaging. Beautifully made, too.
Are the amps in the Airmotiv products actually good Hi-Fi amps? (Hi-Fi is my new old term for audiophile level) It's hard to believe they could be good, and the speaker drivers being good at the same time for, that price. I may just be so caught up in this hobby where money is spent like water, that I have lost all perspective.
I was told by a speaker pro that Monitor speakers were good and not expensive. I therefore believe you about the Monitor 90s, although he recommended a different model. Perhaps I shouldn't be so surprised.