It seems to me that including your switching device in series with the wires that you are trying test will alter your test results. The switches themselves have electrical characteristics that will interact with or over-ride the attributes you are trying to compare. Since we are talking about very small differences between bi-wiring and standard cabling, you wouldn't want to introduce another variable(the switch)into your test method.
BTW I have my M80's bi-wired, I don't know if it provides any benefit, but it is so cheap to do, I figure why not do it?
