Haha well I guess that makes my links somewhat obsolete. Hmm by balanced, do you mean neutral? The HI2050 is fairly neutral with some emphasis on the high end, but you should know that being a semi-open headphone, it really does leak a lot of sound and let a lot of sound in, so steer clear if that's an issue. AFAIK, the Pro 80 is the exact same headphone as the HI2050 aside from a few differences. Coiled cable, pleather pads, and a closed cup for more isolation. For what it's worth, I would personally go for the HD5500. Seems like it's a little higher up on Takstar's list and you'll save the most money on it. I'm jealous of your access to all those Chi-fi goodies.
I like the Pro 80 over the 2050. Not as harsh and better bass extension.
I also have the S500. If you want bass like that, get the 5500 or 6000. The 5500 is like $44 or so in China (i got hosed paying an "early adopter" fee before learning of Taobao.
I like the 5500 the best of all Takstar headphones, even more than the 6000. I posted frequency response graphs earlier.