I have 2 of the big subwoofers. I am merging systems to just have one. So my question is - bearing in mind low values possibly - is it noticeably better to have 2 of these with a surround system or is it a bit of an overkill?

Also there seem to be two ways of setting up? I have an 861v2 but if I update to a v4 or 6 would that change any decision?

Or just sell one and move on ...?