I'd have to say its getting ready to go as well. I mean its always an excuse to get a good converter in there and a fresh trans tho lol.
What I would do is find a low mileage pullout transmission from a 2004 Mustang
. ONLY a 2004. Those are the factory upgraded 4R transmissions and only came in 2004 and you can get them for cheap with lower miles. Only thing you need to do to install one in your car is actually install it and then have a tuner change the OSS pulse setting in your computer from 6 to 24.
Also I'd look at a good stall converter for it while its all out. A good converter will turn your car into a launching machine provided you have a decent suspension setup out back and some 4.10s.