air shocks are not good for mustangs, especially when they're used to support the weight of the car. Remember, they can punch clean through the sheetmetal where they are mounted. I've seen it several times. People pump 'em up so they can fit improperly sized tires, then hit a bump or railroad crossing and the shock comes through the trunk. bad situation........ Only use the springs to control ride height, never use shocks to raise a car. Shocks only dampen the spring, not assist it with holding weight.
Pyro, it would help if you could post a pic, otherwise its hard to say if the front is high or if the rear is low.