On my S-Special Eunos Roadster, the spring has broken on the rear Bilstein shock absorber. Looking on the MX5-Parts website, they only list standard springs for the Mk1. - fits all models 89 to 98. (Other marks do have springs listed separately for the Bilstein’s.)
So, are the standard road springs the right part for the Mk1 Bilstein shock absorber?
S-Special I believe were the same springs up front, @ 167 lb/in, but at the rear went from 97lb/in to 110lb/in.
You could try Mazda; if they are Roadster friendly, they can use your VIN in the worldwide EPC, find the part number you need, and whether it is still available (there is a high chance the spring is NLA). I guess fitting a pair of the MX5parts springs are ok, but no idea if they are made to a MX5parts spec or Mazda spec. The ride will be affected, and probably the life of the shocks shortened (hitting the bumpstop more), but I expect they are already pretty old.
The S-Special rear spring is N021-28-011.Stock manual rear spring is NA01-28-011C.
Thanks for the reply. Now I know what the options are. This forum is a great source of information.