Alex, just to note that the slightly better bass extension of the M80 vs M60 without a sub wouldn't be due to the M80 having more bass drivers: they each have the same two 6 1/2 inchers. The bigger M80 enclosure allows for tuning it to a slightly lower frequency, but yes, this wouldn't be significant with subs handling that area.
As Jason suggested in his preceding reply, a possible M80 advantage would be a cleaner mid-range, because there the M80(along with the M22)does have the advantage of two vs one of the same driver.
