Sonus Faver Grand Piano

... and spell it as "Sonus Faber" or people using search engines won't find your listing.

You can also get an idea of workable selling prices by looking for closed eBay auctions for that item. Are these the Concerto Grand Piano or Grand Piano Domus model?

There are Conterto Grand Piano, Grand Piano Home and Domus Grand Piano. You need to differentiate. If I remember correctly Concerto GP can be bi-amped. GP Home have single binding posts. Not sure about Domus.

kruipen.com

DTC is correct. The original Concerto Grand Piano's have dual posts for bi-amping. The Home and Domus version have one set of posts. The Domus also has two 7" drivers (if I recall correctly). The fair value for the Domus is between $1,800 - $2,300 /pr. The original Concerto and the Home series range between $1,200 - $1,500 /pr. I've owned both the Domus and the Home series. They are all wonderful speakers for their price range.

Sonus Faver sounds like they are Chinese made knock-offs of Sonus Faber products. I doubt they have much value.