I as well noticed oil in this area about 2 weeks ago. I was suspect to it being possiby from the power steering pump, somehow making its way up in this area. (since it was covered in oil) I have since cleaned the areas very well, from top, and from below. No oil around the PS pump, and no oil residue near the intake, as of yet. I am keeping my eye on it weekly, trying to find the source. I would really like to know where it came from.
Bilstein HD Struts
16" E420 wheels