I have this problem too...
1)What audio source are you listening to when you hear this noise (i.e. AM Radio, FM Radio, USB Media/iPod, Slacker, etc.)
Even when I'm not listening anything (audio paused).
2)Have you heard the noise when there is no audio source selected?
"Yes, this is when it's most obvious since the car is so silent it's really the only noise (and it's quite noticeable)"
3)Where do you typically place your cell phone when you get in the vehicle (e.g. in your pocket, in between the seats on the floor, in cubby beneath the display, etc.)
"Between the seats on the floor but also sometimes in the cubby beneath the screen, it doesn't make a difference where I put my phone."
Sound comes not only with the cell phone, but also when the radar advisor (french Coyote model) is switched on.
4)Have you noticed this noise to be more common in certain areas (e.g. Highway 280 near San Jose, Highway 17 in the mountains, etc.)
Often hapens at home.
5)Does the noise seem to come from any 1 or 2 particular speakers, or can you hear it from front and rear speakers?
Sound is coming from all of them.