ok cool. Theoretically what would the advantage be? I'm not going to be using all 9 channels, so I figured it wouldn't hurt.
Well theoretically speaking, some advantages I can think of are :
A. You will have the peace of mind in knowing there aren't any more wires that you could be running to your M80's.
B. In case a tornado rips your house apart, your M80's will be better secured to your reciever than those of us who do not have our M80's bi-amped.
C. You can remove those gold connectors between the 4 posts on the back of your M80's and use them as ear rings.