The FAA has just issued TSO/STC certification for the IFD540.
http://forums.avidyne.com/forum_posts.asp?TID=394&PID=3134&title=ifd540-now-certified#3134
http://forums.avidyne.com/forum_posts.asp?TID=394&PID=3134&title=ifd540-now-certified#3134