This schematic depicts all components used in the 30d 1990/1991 Repair Kit 1 partslist.
The sub assemblies and components that make up this Repair Kit 1 include this Gasket Kit (nas), the most expensive part.
The most reasonably priced component used on the 30d 1990/1991 Repair Kit 1 is the Gasket, Drin Screw (nas).