Alectiong, as others have said having 18 watts gives you the luxury that many SETs don't give you. I loved my Reimyo PAT777 amp but bought Acapella LaCampanellas at 92 db. The 8 watt Reimyo just could perform as it had with the Beauhorn Virtuosos at 103 db. But the Beauhorns were dying at 60 Hz and Murata super tweeters helped a lot. But with no crossover, the Beauhorns were wonderous where they worked.
The guy that bought my Reimyo uses Avantgarde Trios and absolutely love it. I think your requirements realistically cannot be met. The Zus would work, but I have never been a fan. Were you not to have your space requirement I would recommend the Klipshorns, which still seem to me to be the best efficient speakers. I have owned them three times in my 45 year audio experience and often wonder why I ever moved away from them. They do have to be in corners, which was my reason for selling the first two pairs. Now, however, I could put them in the corners with no hole in the center.
The guy that bought my Reimyo uses Avantgarde Trios and absolutely love it. I think your requirements realistically cannot be met. The Zus would work, but I have never been a fan. Were you not to have your space requirement I would recommend the Klipshorns, which still seem to me to be the best efficient speakers. I have owned them three times in my 45 year audio experience and often wonder why I ever moved away from them. They do have to be in corners, which was my reason for selling the first two pairs. Now, however, I could put them in the corners with no hole in the center.