If you are concerned about known warranty problems about your car, Technical Service Bulletins (TSB's) are a good place to start and give you amunition when you visit the Dealer for repair. Many people talk about them here on the forums, but few know where to find them.
The TSB that Ford sends it's dealers are available to the public through National Highway Transportation & Safety Adminstration.
These TSB's do not mean there is for certain a problem with your Mustang. It just means that Ford has seen a lot of repairs for this particular problem, so they send a bulletin out to the dealers so they have general direction with warranties.
The ones listed on the NHTS website are brief and the Dealers version may have a great deal more information. None the less, it is a starting point and I thought the link may be useful. It also contains Recalls, Complaints, and Defect investigations. NHTS Website for TSB's