One problem related to sun roof has been reported for the 2004 Audi Quattro. The most recently reported issues are listed below.
While driving at approx. 45-50 miles per hour, the sunroof of our Audi Quattro allroad exploded. There were no prior impacts, dings, chips, cracks etc in the sunroof. Immediately prior to explosion there was a hollow-sounding pop. The driver was showered with glass which had to be removed from arm, neck and hair. Incident occurred in altitude at temp. At or above 100 degree.