Here's the part needed to add Aux input!
 

Like a lot of others, I've been trying to find a way to add an aux cord to my G37 (non-navigation). I wish I could post a how to video, but I had a local installer do the job, but I can tell you what part is needed.

it is the GROM Audio Nis02A1. It worked for my 2012.
GROM Audio NIS02A1 for Select Nissan Infiniti GROM Audio MP3 Smartphone Auxiliary Adapter Kit-SAT emulation
One downside is they didn't do it with a flush mount. The cable just comes out of the dash. It works great but isn't as clean a look as I would like. If the aux cord ever has to be replaced, I'll have them use a flush mount and install the input on the dash. Only other potential drawback is that this device works off of your XM input, so you wont have XM radio as long as this is installed. You have to choose XM or Aux. For me it was a no-brainer since I don't use XM and like to stream a lot of different content from my phone.

Hope this helps.

Theres a USB port inside the console lid, you can just plug your usb in and select aux, works for me

You must have an iphone. The USB doesn't work for Android phones.

Interesting, kinda weird how it wouldn't support an android