I think, no on second thought I know that BMW tested all the tires mentioned in this thread and therefore installs them on our cars.
I think another point to be made is ... they just don't like to give the business to only one of the manufactures it's just good business to spread it around a bit. For future development and price ... any of you in the business world know what I mean.
I found this article on the Net it is worth bookmarking and reading as well ...
Have a read and yes bookmark it too --->
Click here to Open
... and yes save travels for tires are important
"When the Rubber meets the Road" 