I am going with TCI for the converter inn the mustang. Has 3000 stall should be close to perfect, plus its in a price range I can afford..
As far as the Duratech, IIRC the peak torque is around 4600 rpm. I'd have to look at my dyno to know for sure. That would be insane stall for a family car that has to get the kids to dr's and such
Hard work never hurt anyone, but why take a chance