My 2008 X5 has the same yellowish bronze spots. Originally I took it to the dealer saying the running boards seem to be rusting as there were a bunch of small rust looking dots. After further inspection we noticed their were small dots all over the sides of the car. We came to the conclusion that it was being sprayed on the car by the breaks? Metal on metal and when wet sprays on the car. Needless to say that's why I joined this forum looking for answers. Anyone else with this issue? I've called BMW customer care and put in a complaint. Dealer told me clay bar as well but if I have to do this every time I wash my car I'm gonna go nuts!

O and this is my first post! HAHAHAHAHA

-Marlon