Not sure I get your point. When you burn an "Audio CD," (conforms to that standard format) it converts all your music, whether wav, mp3 or AAC to the CD/AIFF format autmoatically. So the music you purchase at the iTMS can be converted to AIFF format by burning an Audio CD. If you burn a Data CD, it leaves the files as .m4p format. You can choose what kind of CD you want to burn in iTunes' preferences.