2006-2009 DVD drive is used for MP3 / or actual NAV DVD
2010+ drive is used for Movies (when at a stand still...unless coded) / MP3 / WMA / NAV DVD
Now I'm curious as to why...a DVD drive is a DVD drive. So it must be iDrive related. I'm gonna have a look at my NAV DVD and see if I can find a rhyme/reason in the data structure. I'm 100% certian this has been done in the past...but i'll have a look.