The 1A and the Pro 82 feel nigh-identical, with very similar pads and fit. The M2 is a completely different thing, essentially a full redesign, to the point where I was actually a little disappointed with it on a recent brief audition. Not to say it’s a bad headphone, but I was surprised Sony would make such radical changes to the headband and pad design after the universal praise the original design received.
The foam inside the M2’s ear pads is much more dense and memory-foam like, but there’s much less space for your ears inside.
I don’t think you’d see a huge comfort improvement from buying the original 1A over the Pro 82. As I mentioned in the review, the original 1A is just a touch less clampy and slightly better built materials-wise…but the overall wearing experience is nigh-identical. Like, if you wore them both back to back with your eyes closed it would be a difficult distinction. That’s how close the Pro 82’s have nailed the general fit and feel of the ear pads.
Also wow, I’m impressed you’d want more bass than the Pro 82's! With the bass sliders all the way open I found it to have a very high, aggressive level of bass response. But different tastes are part of the fun of audio. :)
Thanks very much for reading and for the reply.