also i noticed something about the 8320s not sure if anyone pointed it out..
but i don't think its possible to have maximum isolation on them anyway... disregarding the shallow nozzle
the part on the "face" of the 8320s where the 3 screws are on have little vents on it that air (sound) can seep in.
along with the fact that the nozzle is short and the port hole next to the nozzle, i don't think it would be good for commuting ( too many sounds would seep in)---> thats only if you want total isolation
i also used this video
http://www.youtube.com/watch?v=lmk-y_9exJ8
in the video if you watch closely, the nozzle had nothing blocking it, and he just shoved in in the mix, without damaging it ( because i image the compressed air inside the earphones prevented any of the mix from getting in... -- > so no vents= no mix leaking inside