...its
www.willtheyfit.com 
What are xDrive wheel? BMW offered multiple wheels for the F chassis 6 series...all of the oe BMW wheels for the f06/f12/f13 fit...the wheels for the M6 F chassis are the only ones you may have issues with due to the wheel offset of the rear wheels.
You can see all of the BMW wheels for the F chassis models (like around 36 wheel selections) on sites like the online part database...here's an example:
https://bimmercat.com/bmw/en/search/...W+640iX/ECE/36
The link above also gives the recommended BMW tires for all the various wheel sizes. You can use those...or go to other tire brands...but you should stick with the recommended tire sizes. If you go outside those recommended tire sizes for the wheel size you have...then use the
www.willtheyfit.com website to try to stay close to the overall diameter/circumference and wheel offset range of the original wheel/tire combos.