I have an older Onkyo TXDS676 that runs 85x5 at 8ohms. It has some stuff about 6ohms in the owners manual but nothing about 4ohms. Is 4ohms to low for this reciever...or will it just run a little warm. I plan to upgrade one day but could always just get a new amp and use the Onkyo as a Preamp. But I am already planning for a full speaker upgrade (m80,vp150,qs8, and outdoor speakers) so i'm trying to spend my $ wisely.