I was talking to g_dogg, but yeah, keeping good front roll center could get tricky. I've learned a while ago that the lowest ride and the stiffest suspension does not mean the best handling most of the times, when it comes to our cars. Even on the track, if you are running street tires, you need come complience, or else you'll be all over the place. This is why I really like suspension setups on BMWs and Hondas, because they mount all the hardware high up on the chassis, and even if you drop them on the floor (check out some track prepped M3s for example), you still end up with excellent geometry. Mustangs were just not designed this way.
There is a way however to have your cake and eat it too. Aftermarket moto is, if there is a will, there is a way. Maximum Motorsports sells tubular K members, that allow to mount control arms higher on chassis, and therefore drop the car lower w/o ruining the front roll center. Griggs Racing whole front end is just built higher up, so if you ever see Griggs car, it's always slammed and still works fine. There is a budget system as well. Racecraft drop spindles allow a 2 inch drop while not changing any of the roll center geometry. All they do is move the wheel mouting point higher up on the spindle. This way, you can run a nice performance spring and sit low as well.