M 528i - Use this site to cross reference which models share the same parts
http://www.bmwstore.pl/pl/katalog/pr...ni-z-pod-gumow
Part# 31356791924 is what comes on a standard 535i here in the US. When i plugged in that number in that website it lists a bunch of cars that also uses the same part and your 528i is included. This means since the M5 bar fits a 535i, it will also fit a 528i.
Alan