I think I'm about to get a full Thule ski/snowboard rack setup and I also wanted to know what is that thing called that I guess deflects the wind to over the rack and makes it more aerodynamic

here's a picture for reference

 

It's called a fairing

 

thank you a lot sir... out of curiosity what length should I get for my car 44" or 52"?

 

I have yet to see a G37 with a roof rack, but what I've done in the past for my VWs and MINI Coopers is measured the distance between the front roof rack mounting feet and purchased a fairing just a hair smaller than that distance (~1" or so.)

 

I guess 44 is going to be it then ! since the crossbars are 53" and as you can see they stick out a bit, otherwise 52 fairing would look awkward I guess...

here's a bigger picture

 

Isn't there one for sale in the private classifieds right now?

 

There is but dont have the cash on me right now and this was more of a feeler than a real consideration buying the setup right now..