That is a beast of an amp for a medium room. 90W rms is a lot. I have not heard the amp in question, but be aware that sony can be a little clinical in sound. I would pare with a set of warm bookshelves. And add a small active sub later. Bose 301 comes to mind. You should be able to find them at a reasonable price second hand. Just make sure the units are undamaged. Cosmetics can be fixed with patience.
It is harder to find good second hand components now that what it was when I started. People were just buying AV receivers and selling lovely equipment from the 70 and 80s for next to nothing.
My favourite mid budget range speakers.have been Missions for years. Boston acoustics and Bowers and Wilkins also makes excellent bookshelves.
The Bose 301 speakers have a special place though. They can be wall mounted or placed on stands and can deliver a warm sound on just about anything.My father's pair has been in daily use since 1983. The suspension was replaced once in 40 years.