I know the 3.8 Mustangs are known for bad head gaskets but is 99 also known for bad head gaskets? Or did Ford fix the problem?
The V6 is plagued with head gasket issues, when not taken care of. Go ahead and prepare to swap the head gaskets around 200k miles. I think that's pretty fair though. If you regularly overheat the car, maybe around 190k or so.