Modest upgrade from Acoustic Zen Adagios?

What specifically are you looking to improve upon?  There's a nice pair of Joseph Audio Perspectives for sale here now that I'd think would be a pretty significant step up if they fit with your tastes. 

Sorry @simao, my iPad for some reason isn't letting me open individual used equipment so didn't realize it was an overseas thing and I hear ya.  There are Pulsars currently available in your price range that are also stellar.  JA speakers are my absolute faves followed closely by Vandersteen and ProAc.  Not that my tastes have anything to do with yours, but if you have dealers for any of those that you can get to I'd strongly recommend you go have a listen to them if you haven't already.  If you don't hear any meaningful improvements over your excellent Adagios, if I were you I'd save up to buy some used Crescendos and call it game over.  That you can upgrade the crossover for even better results is an added bonus.  Anyway, hope this helps in some way and enjoy the search!