The 99-04 rails are all interchangeable AFIAK. The 98 was a one off return setup, the 96/97 were basic return rails and are considered an upgrade for the 98s. But that's just today's fun fact, does not apply to you lol.
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 ****.