need to confirm offset for '06

[818Guy]

Hi. I wanted to confirm the offset on the factory wheels for my 2006 X3. I have the 17x8 wheels. I've seen 46 as the offset but I've also seen 39. Can anyone confirm which is correct?

Also, I was planning on getting 18x9.5 wheels with a 45 offset. Tires will be 255/45-18. Will there be any problems with the front rubbing? Tire/wheel calculators are telling me the wheel will stick out 0.4" (assuming 46 offset on the factory wheel).

Thanks.

P.S. I went to a dealership today and the service department didn't know the offset. Told me to call BMWNA. WTF?