The 98 one might work... MIGHT... Ford started to transition to the HARD harness in 1998 and full implemented it in 99 for the 99-04 run. This is why it so easy to swap stuff between the 99-04 cars including transmission harnesses and computers.
You are really going to want to find one from the same year as yours. I'd call around to local JYs or look on ebay or post up some wanted ads in multiple forum classifieds to see if someone can ship you one.
2000 Mustang GT Steeda build #48. Bolt ons, suspension, Novi 2000.
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.