Synchromesh has been linked to damaging a specific part of our transmissions, can't remember which but I have seen it listed here and Modfords. I use Redline D4 as recommended by those who roadrace Cobra's.
i use mobil 1 ATF, no issues here.
I switched to it and immediately noticed a degrade in shifting cold or hot. I switched back to stock fluid and the shifting was smoother despite temperature. I wouldn't waste the $$$.I am planning on trying amsoil's atf , I heard only good things about it.