From my understanding some of the internal filling also needs to be cut out with a knife.
But yes, I think it sounds best as-is with the old brown pads and the springs in place. Bass control and impact is never going to the best, a bit soft, but it's smooth, non-sibilant with great imaging and detail.
The general problem is that while certain mods might end up working nicely for some, the headphones will sound vastly different depending on the amp, source, cables, positioning on the head, etc. just a handful of other factors involved.