The sub assemblies and components that make up this Oil Pump-oil Filter include this Pump Assembly,engine Oil, the most expensive part.
Parts such as the Oil Pump-oil Filter: Nut 6mm, Bolt 6x35, Stud 6x20, Circlip are included in the Gsx550eu 1986 (g) Germany (e22) Oil Pump-oil Filter parts fiche.
On this parts fiche the Bolt is the most specified component.