Yes, I do know that 94-01 Explorer Leafs will fit my 1998 Sport, but like ibowl9 was saying it is hard to find any with low mileage, so it sounds to me like the 01-05 Sport Traks would be an easier search.
Also you mentioned that the 02 Explorers have IRS. What exactly does IRS mean? I am assuming some type of coil spring, but this is confusing to me because I keep seeing sites that list 2002+ Rear Leaf Springs. I did manage to find a site that listed applicable leaf springs dimensions. I have tried to insert that an image of that site in this post. It shows that the Sport Trak springs are just a bit off (about 1/16") from the Explorer Leaf Springs.
Couldn't figure out how to get the image in so here is a link:
http://thesuspensionking.com/catalog/tables/explorer_mountaineer_navajo.php
I thing the Sport Trak will probably still work in the Explorer.