Skyline R30 pre production models

I was watching some old Skyline documentaries and stumbled upon this little piece of footage where Shinichiro Sakurai sits inside a wooden pre production model of the Skyline R30:

You can see the lines of the coupe emerging into the real prototypes and from the prototypes to the Skyline RS Formula Silhouette. Nice!

The question is: what is that BMW 7 series doing on the test track??

Direct link to video: スカイラインの父 櫻井眞一郎