I finally switched out the arc assembly on the O2. Let me tell you, that was a pain in the ass. But now my O2 smells all leathery instead of smoky. In retrospect, I probably should have sold this pair and waited to get a mint O2, but now everything is new, so I guess that's cool.
A question: I often see the O2 on stands hanging by the headband. Wouldn't it make more sense to hang the O2 by the arcs? It would seem that the stress would be better placed there than on the elastic of the headband. Am I missing something?