I posted this in another thread, but I thought it would be good info to put out:
Just FYI, loading the suspension with jackstands will result in an improper reading. I'm down in the garage now trying to diagnose some vibration issues and the pinion angle is very odd. It's -4*. I know this isn't right because I made a mark on one of the shocks when the car was on the ground. There is still about 3" of travel left for it to be fully loaded. You will either need ramps or a lift.
Just to verify, I called the shop who initially set the angle and they said they set every lowered Mustang to -2* as a standard unless the customer asks otherwise.
Now I could just need some taller jackstands, but the ones I have are over 20" high. Bottom line is that I can't fully load the suspension and I suspect that I'd get a better reading if I could. I'm going to leave it as-is and investigate the adapter plate for my vibration problems.