1. You can, but that is the "port" so your bass will roll off earlier
2. Better but still muddy.
4. The headband is plastic with a cheap piece of foam over it, However the cans are damn light and im picky.
7. Yes (They have a big midbass hump with a SLIGHT sub bass rolloff.) XB700s are the king of sub bass if you like that (I like sub bass, but less punch)
8. If you have the LPs the XB500s are less muddy. However the XB700s are considerably cleaned up compared to the XB500.
Sidenote: I've had the XB500, XB700 and XB1000, The XB500 gives you the most bass, and the least fatigue. XB700 gives you the most sub bass, but less punch and more treble. The XB1000 has considerably less bass than the 500 and 700. The XB1000s were also peaky in areas the ear is sensitive, pass on the XB1000s.
Wow, that definitely added alot of confidence in buying these. I think I'll get them soon.