Well, not sure I'm a bass head, but the reason I purchased the D2000 was mainly because of the bass, with the K167 it's even better, so I'm very satisfied.
And btw, I agree that the K167 needs som burn-in, I just use music, I've had over 50 hours now on it, and the sound has improved, it also plays louder than before, strange....
I can only speak for the D2000 which I had for years, the K167 goes deeper and is more controlled and detailed, the D2000 has a nice bass but it's no match for the K167, combine that with a clearer midrange and nice rolled off highs you have a headphone that sounds great with all kinds of music, a headphone that brings the best out of good recordings, and makes you want to listen to your entire collection all over again, and that's for me the most important aspect
Got a quick listen to the big brother K267, sound is similar, with the K267 you can adjust the bass slightly, build quality is definately better and that's what you pay for, they are not as comfortable as the K167 mainly because they are heavier and they also don't isolate as well, I was a happy though, since the K167 is much better for the money.
I agree, have you noticed how well voices are handled? They are much more dynamic that I'm used to, everything is done so well on the K167, I wrote to Ty from innerfidelity and he will try to get them reviewed