Well, I don't know about you, but I would actually "categorize" them as "basshead"-approved!!!! I was just listening to Pendulum - Witchcraft ... HOLY SH!*#(!(@(!!!!!! Excellent bass response, going oh so low and everything sounding sweet... I think I'm actually falling in love with these! (Haven't used my Denon D5000s in a week now...).
Just did a test with the same song, turned on the "Bass Boost" of my portable amp (c421), and yes... extreme bass, no distortion! (and yes, the headphone is vibrating a bit! lol)
So,... I'm pretty sure that if you get one of those ZO2s, you'll probably be Ok...