Rudeboybass is talking about the LP2, which is a completely different headphone driver-wise than the M-100. He is just saying that he noticed a difference in clarity in those headphones, after a X number of hours.
A driver includes a mechanical system that is the responsible of reproducing the noise, and as every mechanical system, it suffers from wear, fatigue and all those processes that affect them.
The statement that burn-in can make a difference in noise is something that has already been demonstrated empirically (I read an article not very long ago). I don´t really understand what is the big deal with him stating he noticed a difference, even more when as I said he is not the first person stating that. Personally, I am not very good at noticing slight changes in the sound, so I don´t really care, but I don´t feel like the guy to tell him: "What!? Are you insane or something".
In my personal experience the development in sound properties of a headphones is very similar to the evolution of power delivery of a car engine: Some of them don´t evolve at all, some of them evolve really fast during the first thousands of miles, some of them take even more than 100.000 miles to give the best of themselves. Of course, the usage influences on it but, in the end, the change comes sooner or later.
Again, LP2 and M-100 are NOT the same headphone.
Yes the lp2 has a wider isolation ring("dual diaphragm") that separates the inner diaphragm from the outer. They made the ring thinner so that you would get more diaphragm surface on the inner cone for Mid+ high frequency. Could be the lp2 has less bendy stuff so I needs more " loosening up" I haven't got even close to 100hours on the m100 yet but I already experienced an increase in bass impact as a result of the pads wearing in. I used about 20 hours of burn in from jlabaudio.com/burn and am now using every day head time. 2-6 hours