Based on my experience as a Tier1, the assessment for the selection of the supplier is in line with the supplier manual.
Concerning supplier development, BMW has a program called 360deg.
This is more of a workshop run at the suppliers premises, where they do a VSM of the processes dedicated to their product, follow a complaint resolution, etc...
The result is a complete appraisal of the supplier in terms of Quality, Logistics, Planning, Headcount allocation, Capacity, ... and action plan agreed by both parties to follow through.
There is no documentation available at the moment, only if you are assessed and go through the process you are aware of it and how it works.
Hope it helps
