88-89 i believe 89? any who they have the seatbelts like a reg. civic, the 90-91 have the seatbelts made into the door/panel...therefor the seats are obviously different...i had this same problem, only i had an 88SI...tried to put 91SI seats in thinking ok there both SI's why wont they work? then i dawned upon me the difference...maybe this helps you maybe not but just my .02 cents...