Just an FYI for Nissan NAV v6.6

I have successfully backed up my DVD. Here is what I used:
1) Verbatim DL DVD+R
2) ImgBurn
3) Lite-On burner

I used ImgBurn to create the ISO and MDS files on to my hard drive, and also used it to Burn the DVD. I did a regular burn, as well as changing the book type to DVD-ROM through ImgBurn, and they BOTH worked flawlessly.

I also played around with a DVD-R single layer by cutting out several files to make it fit. However, my Altima did not recognize the DVD. Perhaps I can try using a single layer DVD+R with limited files to see if that works. Perhaps it would be a much cheaper way to back up the DVD if you only plan to travel within the same area

Hopefully this information is useful to somebody