Yesterday a set of leather W5000 pads arrived for my AD900. They fit perfectly and there is something about leather ear pads. Mind you at $100 Aus ($86 USD) a bit extravagent.
Now, I have changed pads before, MS2 and MS1 (bowls , comfies, mod sens) and for me the sound difference was only minor (I know other Grado/Alessandro users will disagree) and I even have pleather and velour pads for my Pro 550, again only fairly minor difference in sound change. However, switching rom the velour AD900 pads to the leather W5000 pads has produced quite a marked differnence in sound. I didn't find the bass of the AD900 stock as lacking, however many users have described it as a bit thin. Well my advice is to try it with some leather or (pleather Axxx series) as it really has some significant bass impact and slightly overall warmer sound, without sacrificing the soundstage, or sweet mids. I currently have a very bad cold/flu, so i don't trust my ears at the moment, but I will do a full review when my head is functioning properly again.