Nice thread...important topic for all V-Moda owners.
Not being a troll or raining on the parade here, but wanted to offer a cautionary tale. I have a love/hate thing going on with my new XL pads, but it is trending more towards love. First of all, I did not find these things easy to install. Had trouble removing the stock pads, a little tearing in one, a lot in the other : ( Then had some trouble getting the XL pads to snap in securely. Ended up using the tip of the headphone plug to very gently press around the edges as I could not get things snapped in with just my finger pressure. You should see a single seam in the pads, they go at the bottom of the cups, as does the slightly flattened cut of the plastic opening on the inside. Some slight panic over this as I didn't notice any info on proper orientation of pads until after I was done. But all was well.
Tried on the headphones without music first, and what an awesome upgrade in comfort! I was patient with the stock pads and they seemed to work OK with me. I was coming from an Audio-Technica ATH-ESW9 and those things are known to require much patience and experimenting before the pads and your ears find a way to get along with each other. Also, I have big ears, just barely fit well inside most sennheisers and many new "around ear" designs from other companies end up being "on ear" for me, M-100 included, though the new XL pads give me enough room to squeeze everything in most of the time.
Music was a different experience. Overwhelming bass and a new sense of thumpy/tubby sound that really ruined things for me. Did not notice any improvements in mids or treble (not that they needed improving) or in soundstage. Now granted, I did not find the stock config to be what I imagined a "bass head" headphone would sound like, but the bass was stronger than anything else I had, and in a very good, very satisfying way. With the new XL pads, I was not satisfied. It felt a little warmer and isolated as well, felt like I was thrown in a closet with a subwoofer. I think this all goes to show that not only do we all hear things a bit differently, but that the physical interface between headphone, head shape and ear shape can also be a very different and very influential variable between many of us.
Anyways, I don't know if the pads have compressed a little or just broken in and shaped a little more to my head/ear, but things seem to be moving back in the direction of the stock sound for me which is a good thing. Bass not quite as ridiculously out of balance with every thing else, and tightening up so that I no longer hear a muddy mess. I am hoping this evolution continues just a little bit more and all will be perfect. I can't tell you how impressed I have been with the M-100 in general. Forget the bass and style points, just in overall sound I think they hold there own with many well known audiophile headphones. So I am still a big fan, but the pad swap has been a roller coaster for me. YMMV.