Roth_s, I really appreciate your step by step modding instructions. I have yet to mod any headphones but I plan to mod these pretty soon. I hear too many good things about modding the HD668Bs. Also there is great links about modding them in this thread
I bought AKG k240 velour pads today and I'll probably get an portable amp and maybe a better cable (I've never actually researched what different cables do for headphones since these are actually the first pair of headphones I've given proper care for).
I'm gonna want to figure out the best way to boost the lower mids