Don't know which one is really the same or very similar. Why do you want to have a "copy" of the oem castrol stuff?
If you are just looking for an oil which won't harm your engine or your warranty (and fits your car) just go with an approved BMW Longlife Oil (for example 01 should fit your 2003 M54).

I'm using Mobil1 over 10 years now in all BMWs and am very satisfied (no beige smear/clog for example if you are driving short distance). But this is very subjectiv, everyone swears the oil he or she is using will be the best because of something