Edited by gopanthersgo1 - 3/11/13 at 3:20pm
Some people have complaints of their ears touching the drivers because stock pleathers are a bit too shallow, so the hard foam rings are a hack that Hifiman did to resolve that issue. If you have ear-touching-drivers issues then the back-vents mod should be sufficient to resolve it, without messing up the sound.
Np. I answered that here actually: http://www.head-fi.org/t/619447/hifiman-he400-he500-re-grilling-mod-56k-dial-up-users-beware/90#post_9249483
Thanks. I should have them tomorrow and wanted to make sure it wasn't too difficult to get the J$ money pads on. How do the J$ pads compare to the Jergpad mod?