I used to have the sonos amp driving the Elac unifi slim bookshelf speaker and it was having a hard time driving it and their combination sounds awful in my taste. I would maybe try their newer uni fi 2.0 floorstander. I heard good reviews on their newer 2.0. I had experience running the sonos amp with Kef r3 and those sounds pretty good. Specially if you also have a sonos sub, it blends well with the amp. The sonos amp is transparent and it matches the R3 well. I also tried the sonos amp with bowers bookshelves and it might be too bright for your taste specially on music. But bowers are awesome if your using the amp as a home theater, it's very detailed and clear.