Take it back and tell them to put 2005 Mustang GT specs on it.
What specs would that be?
+7* caster left and right, -.75* camber left and right, +1* toe.
Obviously they won't hit the caster number, which is fine as any positive you can get is better than stock, but it gives them a late model target that will be in any alignment computer, at any shop, nationwide, that any toe and go tech can likely perform.