Good used ring and pinion set removed from a BMW differential. Each set is cleaned and glass beaded before it leaves to ensure it is in good shape.
When installed in E24M6, E28M5, M535, E34M5, or non M V8 cars which came with 12mm ring gear bolt holes in the carrier, the carrier will need to be drilled out to accommodate the larger bolts. You will also need a 14mm ring gear bolt kit.