my 8.5 is doing this as well...and i think it is coming from the seat belt area too. took me forever to find out where it was coming from, cuz i would hear it and try to duplicate it again by moving all around, so my wife was looking at me with a strange face when i was squirming around. she thought my 'roids were acting up or something
later i was able to duplicate the problem everytime when i breathed in deeply, my diaphram would lift the lap belt up and thus move the base of the belt and make the noise
and on a side note, i'd also like to say that this is by far the noisiest car i have ever driven, from this seat belt squeek to dash rattle to the stiff suspension/tires amplifying all sorts of road noises, the blend door is making noises now when i change vent settings, and now my driver door window motor is clicking when the window goes up and down
yet i haven't had any driveability or engine problems, weird