Yes, the Fostex T50rp is one of the most modified headphones around. I own the ZMF Classic which is one of them.
“They do all sorts of tomfoolery to make the sound a more personalised experience. There in is the key I suppose. It’s the actual tinkering itself that gives the pleasure and if you hit on a good amount of improvement then your laughing.”
My thoughts exactly about tinkering and finding the sweet spots 