Hi All,
Have the same problem with my E53 X5. The dealer did not want to know about it and said they never see it (BS in my opinion). I even brought half a ream of paper from this forum and others on how common the problem is. Anyway, brought back to my normal service guy who was with BMW for 15 years and started his own specialist BMW service centre. He said they have fixed quite a few of the X5 sunroofs. He has quoted around $900 AUD (about $3.50 USD

) to fix it. So my advice would be to look around before shelling out the $4000 USD quoted earlier in this thread.
PS... Love this forum. My wife already says when I get on the computer "let me guess, you are on X-outpost again"... Any cure for the addiction?