I used the standard kyb GR2 1995 mustang rear shocks. You dont have to modify the bottom like you do with the crown vic shocks. The only thing I had to do was trim the rubber part that is at the top of the shock as it seems the Mustand has a bigger hole for it to go through.
btw, I just finished doing a write up on installing Jeff's kit in the "Build Diaries, How-To, DIY" section that might be of help in getting ready.