here's my set up.
oem cross bars and thule moab.
with cross bars on you'll hear some wind noise. with moab on you'll hear a sure increase of wind noise along with some rattling (couldnt figure out where it was from even after securing everything down multiple times) even with the diffuser on.
http://www.flickr.com/photos/39553560@N00/
i love the look, but until i figure out where the rattle comes from, i am not going to leave it on permanently.
Very cool - I have the OEM bars with OEM luggage rack. It was so loud with the luggage rack that I couldn't stand it. Now I just have the OEM bars up but I still hear the high pitch swoosh sound. Now I am thinking about taking the OEM bars out also.
How is the diffuser working for you?