Not sure if you ever figured out that the hose to the stock air box is the Air Pump. Here is a link to a discussion of it:

http://www.xoutpost.com/x5-e53-forum/...ram-found.html

I am considering removing the air pump entirely when I get an air intake.

How is the sound of the AFE CAI? Anyone able to compare the sound of the AFE vs the Dinan?