To followup with my post. I had returned the car to the dealer for two reasons:
1. The clunk noise when the sunshade was closed
2. The sunshade did not rest against the rear headliner (3/8" gap between the headliner and sunshade). The original sunshade (MY2005) is not compatible with the "redesigned" sunroof cassette.
The dealer had to order a new sunshade, this solved both the noise and the fit to the headliner. He informed me that the original sunshade is not compatible with the redesigned cassette.
The cost to replace the cassette was $2800 parts and labor.
The "redesigned" sunroof cassette solved all of the rattling issues I had with the original sunroof.
The "redesigned" sunroof cassette solved the buffeting noise that occurred when the sunroof was open (on my old sunroof to solve the buffeting noise I would lower the rear windows by 1/2")
Very please the dealer did an excellent job.
2005 X3 3.0, Mystic Blue Metallic, Sand Beige Leather Interior, Birch Grain Light Wood Trim, Steptronic Transmission, Premium Package, Heated Seats, Privacy Glass, Satellite Radio Prep, Xenon Adaptive Headlights, Heated Steering Wheel, Premium Sound, Power Folding Mirrors and NAVIGATION RETROFIT