On the 4S lipo and MM yes, I have run a 7XL on 5s through a MM, and while i don't tell people to do it, it did survive
I have been doing the same thing with a 9xl motor. I am going to go back to 4s though because I think the 5s might be a little to much for the mm.
I will probably end up going back to the higher voltage when the mmm or quark plasma come out.