We can't assume the HP drivers in the M60 will result in higher power/SPL. The crossover may not be designed for it. If you want higher power and SPL, you may have to move up. But, I'd bet, within its power and frequency spec, the M60HP is more linear than the M80.
As for the M100, the M60 is more linear. I've said it many times before and I'll say it again. I like the M5 bookshelf better than the M100. The M100 goes louder, forms larger images and soundstage, sounds more real but it also gets in the way of itself when it comes to imaging. The M5 is invisible and I didn't even have to try. So is the M2 and M3. But the M100 is not - not in any of my rooms. Sure, I may be encountering "position error" but I can only spend so many hundreds of hours trying to find the right position! So now that I know the M60 comes in HP, I presume it sounds as good as the M5 and it comes within its own "stand". It goes lower too.
I suppose it depends what's important to you. Acoustic invisibility, or lack of audible resonances, is paramount to me.
As for the ALFRs, unless you plan on throwing dance parties, you don't need them. The passive Axioms are that good.
