Several pages back and a few weeks ago, Arnaud gave an eloquent explanation, along with measurement graphs, of how very loosely woven material in the cups result in the perception of greater space or soundstage (I hope I accurately paraphrased, Arnaud). With this in mind, it might be worth a trial if you care to try out the "Less is More?" mod or the "Transpore mod" I posted a few days ago. They include reversible mods of Paxmate Plus in the cup bottoms, tungsten putty in the back baffles, Dynamat around the drivers, paper lifters under the rear side of the pads, and all else stock:
Take a medium (I know, what is "medium?") 100% cotton ball and tear it in half. Tease it out in all 3 dimensions until it is the size of the cup bottoms and about 1/2" thick. If you hold it up to the light, it will appear very thin an porous. Place one in each cup between the Paxmate and the tungsten putty (or plasticine). Next, take two Kleenex tissues and fold them over and then roll up into 5" x 1/2" 'ropes' and place one under the back side of the ear pads.
I think the reason I did not achieve good results with cotton in previous attempts is because the cotton was too dense. With this very light and open cotton "puck", well, I'll leave it to you to form your own opinion.
If you no longer have the stock white driver material in place, and if you are looking for an alternative, Transpore is pretty dang good stuff. You can tune for bass heavy with 1 layer, bass medium + nice treble with 1.5 layers, or bass light(er) + accented treble with 2 full layers. I've found that 1.5 is the "sweet spot" for me with 2 strips of 3/4" Transpore applied to the back of naked drivers (with about 1/8" overlap) and 1 strip applied perpendicular and on top of the first 2 strips. What is more remarkable is that I have not heard bass bloom into the midrange with any of these 3 configurations.
As always, my comments are offered for your consideration and trial: IMHO, My 2 cents, IME, and YMMV; sounds good to me but you make think it sucks. It's all good.