Jakewash has had both, I'm sure he'll respond eventually. If I recall, he did think the 160 was better for off axis, but found both to be excellent with some points going to each in different categories.
JC - good input. I was simply going off my experience with my M80's. I do not have a golden ear, but it was quite clear to me that in my application, they sounded profoundly better with 12" of clearance (or more) from the back wall. This was one of the reasons I moved downward to the M60's. I needed the added floor space. The M60's seam to much more forgiving than the M80's.
