My advice is DON'T buy the Onkyo 875. I have one running pairs of B&W 683, 684, & 685. The speakers are awesome and the amp is awful, as in very disappointing. When new the amp would trip out if I tried to play the volume above 92 for more than a minute, this was solved by changing all the hdmi leads for QED Qunex-SR. Now the amp would run to 100, but after about 9 minutes on max with Pendulum the onkyo died. It went back to onkyo who changed the 'power transformer'. They would not elaborate beyond that other than to say 'possibly a surge of electricty had killed the transformer', even though it is connected through a Belkin Surger Master,(maybe I can claim on Belkin's insurance???). So I got the amp back, connected it all up, ran it for a while normally before turning the volume up to 100. It lasted 15 minutes of Pendulum before once again the transformer seems to have blown up. I am taking it back to the shop today and hoping to change it for something more robust.
Negatives of the 875 are, GETS INCREDIBLY HOT, AND BLOWS UP IF USED ON MAXIMUM...
And yes, the system was set up by the shop, the speakers were all calibrated, etc.