If you want Sooloos on 861, I guess you need to fork out another �2k.
Don't think this is the case
The Sooloos Card for the 808/861 is to allow you to ACCESS your Sooloos System from a DIFFERENT Room
In your main Music Room, you can Input your Sooloos thru the standard Speakerlink Input and then control it in the "normal" way
No imagine if you have e.g. a "Family" Room where you still want to access your Sooloos (in Sonos terms, think of Zones) then you would put the Sooloos Card into your 861, which allows you to control your Sooloos system remotely from that room using your MSR+ (only for currently playing Playlists however, according to the various CES Releases)