Hi readster1,
It's a good thing you were using a big amp because it's unlikely that the signal was clipped. I think you'll be okay, because we have tested the M80s with as much as 1200 watts without any damage.
A smaller amp might have sent a big clipped signal through that would have caused serious damage. You could run some pink noise at medium level, and put your ear close to each driver to make sure each one is working.
Tweeters usually either work perfectly or not at all if they are damaged.
I've never had reports of this with M80s, but some damaged woofers on other speakers make scraping or buzzing noises if the voice-coil former has become misshapen or warped and scrapes on the magnet pole piece with powerful bass signals.
Regards,
