I had to look pretty closely to see what was ‘special’ here.  In case you have a hard time finding it, apparently it’s that, “The clip is laser engraved with several stylized 7s and an individual series number.”  (I guess that if yoiu have a 3 Series you’re stuck with a Lamy.)  It’s not clear that there is any special engraving on the nib, as on many Montblancs.  Oh, there’s leather stuff too, in addition to the fountain and rollerball pens.

BMW and Montblanc present “Montblanc for BMW” Special Edition

http://www.bmwblog.com/2015/09/09/bmw-and-montblanc-present-montblanc-for-bmw-special-edition/