From what I can tell, the noise is coming from one of several places:
1. The plastic cross piece wind deflector in the middle of the roof.
2. Something in the mechanism/parts at the front of the roof.
3. The sliding sunshield itself. (least likely culprit, but possible).

Here is what I have done so far to quiet mine:
1. Raise the sunroof in vent position. Take a total of six round self adhesive felt discs, 3/4" size - the ones that go on the bottom of chair legs to keep from scratching the floor. Adhere one felt dot to each corner, and one to the center of the BACK of each sunroof panel. When you close the roof, you want the felt dots to rest against the plastic crosspiece of the sunroof. Doing this quieted about 80% of my noise.

2. Open the sunroof fully. Get a can of Jig-A-Loo (from Home Depot) or any good quality Silicone or Teflon lubricant spray. Generously lubricate the sliding tracks and the hard rubber gasket that runs around the roof.

3. Open the sunroof to tilt position again. Spray the lubricant on the lifting arms, springs, pretty much any & all moving parts that you can see. You might have to use the little straw to spray behind the rubber bellows on the sides of the sunroof.

My noise is about 80-90% gone. Still get the occasional weird rattle on a very big bump or rough road, but it's not terrible. Not even sure if it's worth a trip to the dealer. I'm sure it wouldn't be covered by my CPO warranty, and God knows how much the stealer would want to diagnose and fix.