Dan, the GMs spend most of their time above 4 ohms. You can explore the 8 ohm tap but pay attention to the bass where they do drop down. I found that the 8 ohm tap sounded better at times and other times it was the 4. Then I figured it was the content of the recording in terms of bass that swayed my preference back and forth. I settled on 4 ohm as the permanent tap to use when I ran the 275.
