Well then you heard wrong. If you keep the same ride height then nothing else changes - camber, caster, tie rod adjustment (toe), tie rod angle (bumpsteer), all will remain unchanged. If you lower it you will have the exact same alignment problems as you would get with conventional lowering springs.
Read here it says you can use with stock k and a arm, or even call them and ask their tech. They are very helpful and they have the best quality and most proven products.
Maximum Motorsports Mustang Front Coil-Over Kits
EDIT - I forgot on 94-04 you do have to upgrade your caster camber plates to 4 bolt ones since the factory plates weren't designed to support the entire weight of the front of the car.