I've done the Kramer mod to mine and they sound quite good- I'm listening to mine on my full setup right now just for kicks. 
My only concern with these is the quality- what I'm wearing is a combination of two sets. The cable died on one after a few months and the driver simply quit on the other. But what they seem to lack in build quality they more than make up for in sound. I remember comparing them favorably to my HD-280 when I still had them around.
Edit: I just put on my favorite version of Rhapsody in Blue
and I... WOW. Sure, there's some distortion towards the end of the opening clarinet glissando and some other flaws, but I'm astounded at what these can pull off. Easily worth more than the asking price.
Edited by MCC - 7/6/10 at 5:57pm