I know this is a late response.
I am running Dali Helicon speakers with the AVR600. Honestly i tried it both with and without biamping. I didn't feel it was necessary. Difference was minimal at best and far more difficult to setup properly. The Dali's are 4 ohms so this unit has more power than I can ever use even in a large room. Instead I ran the additional 6 & 7th output to make it a 7.1 system. Was worth doing although there aren't many 7.1 discs out there the EX material does OK but in 7.1 it is amazing what this receiver can do.