Hmm, about the D2000, I have a related question.
I'm using Touch 2G LOD + Mustang + IE8, which have been working perfectly. However, I wanted to get a full size headphone to use at home that can provide the punchy bass that can't be found in IEMs. After a bit of research, I found that D2000 seemed like the ideal phones for portable amp + source, since it doesn't require as much power.
Upon auditioning D2000 at the store, I noticed every single song I played was distorted and sounded worse than FM radio. I noticed that barely any bass was present even in heavy bass songs. The mid sounded.... well, for a lack of a better word, grainy and lo-fi. Many songs also appeared way too bright than usual, basically I could not find a song that was satisfactory to listen to. I tried playing songs in different bitrates, but none was any good, or even close to what IE8 can produce. Additionally, I tried the various gain settings in my Mustang and none helped. Needless to say, I went home without the D2000 today.
What I'm wondering is, does anyone know which part of my configuration is causing the problem? The problem caused by me not using lossless? (My songs are in 320 and 192 mostly) Or it is because Touch simply sucks. Or is it because Mustang is not a good fit with D2000. I think I must be missing something, since I've never heard anything half as bad out of any other headphones.