Beyerdynamic sells a repair set with a coiled cable, suitable for the DT770. On their german site it is listed with article number 973779. Pads can be changed as well... According to their FAQ the main difference between velour and soft skin pads (default with the LE) is the isolation: the latter isolates more.
Also according to their FAQ the sound difference between the PRO und consumer versions is due to increased pressure due to the stronger headband on the PRO versions: better isolation but a little less detail mid/high and a bit more bass. They do not elaborate on the pads changing the sound, but I think the velour might give a little less bass as they do not seal that much.
Disclaimer: only deducted from Beyers german FAQ. I did not try out the other variants of the DT770.