I've helped or lowered over half a dozen Mustangs, and every one I measured before lowering and after...every single one in stock ride height was off by 1/2" to over an 1". When the cars were lowered, some came closer to being centered and some not. If it's a daily driver and you only track it once or twice, or if you take it on the twisty roads for fun, just measure it the way it is and see if it's off center. If it's within 1/16 to 1/8" off, then don't worry about it, if its more than an 1/8", then it's up to you. If you don't lower the car and the measurement is good, there's no need to spend the money...IMHO