Just wanted to bump this up, since I don't think this is getting the attention it deserves! You can "test" the mod in a completely non-permanent/temporary way, and it will sound the exact same as if you had done it permanently. I thought maybe the drilled hole cups vs cups completely off would sound different. Nope. Did a back-to-back comparison, and the size of hole I drilled is all they need. Same thing goes for the velcro under the earpads. As long as they have that room to breath using the height that the pegs give it, they'll sound the same with/without velcro.
Perhaps I should start my own detailed thread on the D2000? I'm not sure why this isn't getting more attention, since the Markl mod was extremely popular. I guess the Denon headphones aren't as popular as before?