I go on 4chan every day, and whenever I see the Sennheiser HD598 mention I see the "foam mod" mention. Something about making the Sennheiser HD558 sound exactly like the HD598. I'm skeptical and curious at the same time. I'd like to get the best headphone but I'm curious to know if anyone hear has ever heard of the foam mod.
Here's the video showing how to do it. http://www.youtube.com/watch?v=r8i_ZGHHhuQ