This question come up a lot.

You want to leave your receiver on 8ohms switch setting, even though some of the speakers in your setup might be 6ohm or even 4ohm (m80's).

M80s VP180 4xM22ow 4xM3ic EP600 2xEP350
AnthemAVM60 Outlaw7700 EmoA500 Epson5040UB FluanceRT85