It has been a long time since I have posted something here. I was busy, and lazy. Ok, so I bought this Fostex T50RP and received it about a week ago. Coming from AT M50 and Shure 440, at a first listen, I thought - "Baah, this is so flat, boring...". After a few hours, I thought - "Ah, this is very flat, interesting!". After a few days, I really thought - "Wow, this is flat and neutral, I like it!". Then I decided to begin the modding process. The first thing I have done was simply replace the stock pads for Shure 840 pads. Then I listened with this pads mod only : I was blown away by the difference in sound signature! No modeling clay on the baffle, no Transpore tape, no felt for damping, nothing more than Shure 840 pads and that's it. The difference is so big that I doubt that any further mod is necessary. It just sounds perfect to me.
I think the Shure 840 pads is responsible for the major part of the improvement. I suggest to anyone who don't want to spend hours on modding, or don't want to open their T50, to only change the pads. It will make a huge difference in 5 minutes.