I decided to to check my air filter today (11k miles on the clock) and I noticed that the filter has a 1/4 inch layer of foam below attached to accordion element. Now I have build a motor or two(yes they were Ford engines) and feel that I know a thing or two about engines(worked on all my cars). Now why does BMW add the foam element in addition to the paper filter... I am not talking about the Carbon filter but the foam attached to the "official OEM filter"

 

mine has the same, Im assuming its more added filter protection.