I have the ONKYO TX-SR800 and have been running it with 80's, VP150, QS8's and M22 rears. It is usually in all channel stereo and has been set like this for about 1.5 years. The receiver will automatically switch to Dolby or THX depending on the input signal so I don't change things around too much. It has not even sputtered once and it has been at very high volumes at times. I don't think the newer version would be any less dependable with four ohm speakers than mine??