A few days ago I rediscovered my M50. Miss those as well, to the point where I decided it's time to upgrade to M50x lol!!! And while I was playing M50, pulled Dolphins out, but their upper mids sounded weird. Makes me wonder if it was a bad idea to remove those foam inserts (which I threw away).
I have M50 but have not heard the Dolphins. I think I may want to get the Dolphins from Penon Audio. I just bought Havi B3, the old version, from Penon and the shipping was quick. However my initial impression about B3 is that I think VSD1 sounds better.
Regarding Dolphins, I read about the foam mod and always wonder if there was a reason that the manufacturer put the foams in there in the first place.