I'm sorry, I must have missed that. I was just always taught to identify the problem before replacing parts. Most of my competition here locally (at least the independent shops) go with the theory of "let's throw parts at it until it's fixed". There's a good chance that a new MAF will help your problem, but there's no guarantee. With so many Mustang people in your area, I would think you would know one. Aren't there a bunch of people on here that live near you?
Anyway, do what you have to, I just didn't want to see you waste any money.
Take care,
~Chris