I think you will struggle to find a single sports seat very rare to see just one
Standard seats you can get singles but as there is value in M and Sports seats they are usually sold in pairs.
Also if your car is a 98 you will need to check if it has the earlier 3 multiplug setup or the later single multiplug think it will probably be the multiple plus as 98 is when they started messing about with stuff my 99 pre face-lift has a code on its spec list for 98 on model mine is a mixture
Seats are old plug but my airbags , abs , engine and lined roof are all the later designs.
Stephen.