Escaron, hopefully as you become more experienced with high quality audio equipment you'll learn not to take seriously reports of amplifiers being either "bright" or "warm". Since it's routine these days for even moderately priced units to have an audibly flat response from 20Hz-20KHz, one would have to designed with gross incompetence to have the major frequency response inaccuracy that would be necessary to exhibit an audible coloration.
No, "a lot of people" haven't said that it shuts off when the M80s go beyond 100dB, and as long as it doesn't, that means that the temperature is within acceptable design limits.
You got an excellent price on the 876 and at this point you should assume that since it's a quite powerful amplifier that it will power all your Axioms to very high levels and that no separate amplifier will be needed. Stop worrying about problems that are highly unlikely to develop and just enjoy.
