To put this in perspective for a few folks on this thread, I have had exactly 3 distinct disturbing noises.
The first noise comes from a friction plate in the front right and left. Apparently this is between the rotor and hub and assuming this has something to do with design pieces around the front heat shields. For this noise, see my video posted below. These friction plates have been replaced for both my right front and left front.
The second noise I heard was definitely a pebble in the rear, which sounds liken to what most people describe as metal on metal "grinding". This is a much louder and more shrieking noise than the other noises I've heard. I had one of my neighbors comment that she thought something was falling off of my car and I had to embarrassingly tell her that it was just a pebble stuck. Additionally, this sound is recurring and screeches as the wheels go around each time, but it can be intermittent depending on speeds and possibly (how big the pebble is?).
The third noise I heard (it's only happened once) is the noise that I think many people are referring to the "soda can crunch" noise. I heard this at low speeds in my work parking lot or pulling to the light out of our parking lot. It sounded like I ran over a soda can or something metal and was a loud crunching/rubbing noise in the rear. I looked back and saw nothing. That sounds like what most people are hearing other than the pebble screeching noise.
I'm not sure what caused my first noise (it's happened twice now) and both times the dealer replaced the friction plates/shims. I had my left front replaced the first time and then the second time was the right front. I now have about 3100 miles on my car and have not heard any of these sounds in the last few weeks. Hopefully this may help clarify some of these noises that folks are hearing.