guys--
anyone with an older SC or any other car that has those seatbelts needs to check into this....last time I knew, Mazda had a similar issue with certain years of the RX7, and because it is a required safety feature, it is supposed to be warrantied for the life of the car. I have known a few people that have gone to the manufacturer and gotten it fixed like it was a recall--no cost.
Worth checking into if you cannot find the needed parts at your local boneyard. Also know this--even if you do find the parts, they are coming out of a used car, and those used parts have already begun to wear.