You will find these questions and many others asked many times here on the forum.
Sorry I cannot answer them for you,
But if you search for your answer here it may help to answer the question.
I would thing that even on vehicles like BMW they may have used different catalytic converters with differing amounts of PGM's, and possibly even different formulations of these metals for different years of vehicles made.
also probably the only way to tell for sure would be to for you to test them and see how much metal you can get from them.
