Can you post up at least one of the BMW 11 digit part nbrs that you're unsure of which would help paint a clearer picture (and give the forum some details) of what exactly it is that you're having trouble finding? Help us help you better...I don't know your model of e53 X5 or if it is the front or rear axle wheel hub info you're seeking.
Having the last 7 digits of your VIN would be the biggest help for any forum member that has access to part database information...without it is searching blindly which after a lot of search may stumble upon some info...but again, we don't know which axle nor which model X5 you have so the info could be wrong.