I think Oh2freshstang has the perfect advice for you here. Making sure you have the correct pinion angle, is crucial when using an aftermarket 1piece driveshaft. The best way to make pinion angle is corrected is to use an adjustable UCA
. Then you'll be regain the factory suspension's geometry as well!
I wouldn't be to concerned about bottoming out with a 1.5" ride height drop. It's not significant enough to cause an issue while driving, IMO. I would be more conscious when you're parking, but that's about it. You can still take speed bumps straight on, as long as your not flying over them! Plus, we do have a curb alert parking assist sensor, that you can mount under your front bumper to help judge distance when parking.
Check out the video below if you're not familiar with the parking assist sensor
. It's pretty helpful!
Mustang Curb Alert Front Air Dam Sensor Review - YouTube