Hi Socketman & Oakvillematt - I agree with you both.

Axiom is a stand-up company.
Emotiva makes excellent amps.
A sensitivity number is never enough to tell you how speakers will sound.

However, the "sound limitation" I was getting with my M80s wasn't due to lack of power.
I ran my M80s with a Crown XLS-1500 (525 watts / channel @ 4 ohms)
I ran my M80s with an Emotiva XPA-1L pair of mono blocks (500 watts @ 4 ohms)
I ran my M80s with bridged Crown PS-400s (~1,000 watts @ 4 ohms)

With all of these amps, the speakers sounded slightly bass-shy in my room. When I paired them with one and then two subwoofers, however, the sound became more balanced.

I'm NOT a bass freak. I don't like boom-box sound (despite my moniker). But cone area and bass distortion matter. The Axioms (M-80s and M-100s, both) still use relatively small drivers. That means that to produce bass volume, the drivers must use more excursion, thus increasing transient intermodulation distortion.

Mr. Colquhoun, being aware of this, introduced the three M-100 woofers with larger magnets, cast baskets, and greater excursion than his previous woofers. The greater cone area (from the extra woofer) reduces TIM, and the greater excursion allows higher volumes (although with a necessary return of some TIM).

How successful will this strategy be? Watch for my review on the Secrets of Home Theater & High Fidelity website.

That is, if I ever get the speakers! LOL The order was placed Dec. 15th, but my account page shows no shipping date or tracking number yet...

But ultimately, bass is bass, and there's no substitute for driver area (unless one uses a bass horn, as does the legendary Klipschorn). Knowing this, Axiom provides a full line of large-cone-area subwoofers. But I'm trying to avoid subs for WAF reasons. Will the M-100s provide sufficiently plentiful (and sufficiently clean) bass that I can dispatch the subs to the local CraigsList? Stay tuned...

My opinion is worth exactly what you're paying for it!