after thoroughly studying this and listening to the samples, I would say the differences are subtle. however, I'd really like to listen on a better playback system. my mk-012's are from guitar center, I believe I'm betting some help in getting them modded.
but anyway, check the archival section for brian's thread on the mc-012 mod. for even more info, leaf through the pages of this very forum until you find the original thread about the mods, there's some links in there to some samples I believe.