Drmurray,
Hmmm. That's odd. Who did you talk to at Axiom? Too many flaws will be exposed in the electronics? That's nonsense.
The M60s are easier to locate and move about (not as heavy), but assuming an 8-ft ceiling, you have 6,800 cu ft to fill. Actually, the M60s will be play very loud so you should be fine, but the aforementioned comments puzzle me.
I would have suggested the M80s for that enormous basement, particularly since you have the Denon 4802. Did the Axiom guy know that? All the Denons will drive M80s; likewise the H/Ks. They are the only brands of A/V receivers I recommend for the M80s (new NAD as well).
In answer to your other questions:
2. No.
3. Break-in is a myth. You are breaking in your brain and ears to a new set of reproducers in a new acoustical setting. The characteristics of the speaker do not change, even over years.
4. Don't know. Try the Denon site.
Regards,
