My friend claims that he fix his headphones in the labs of Beyerdynamic, and they set one of the drivers to gen2 one. do you think that this could damage the sound quality? is this ok? is it possible to mod this driver and return it to work like gen1: I see from this picture http://forum.avmania.e15.cz/download/file.php?id=57206&mode=view that they Beyerdynamic add some plastic addition on the gen2 driver? (maybe is removable). do you recommend me to buy this headphones from him?