It is listed as a 4-CD changer. Not a DVD. The DVD nav only plays the navigation disc. I have the Mark Levinson DVD Navigation on my Lexus IS350 and it is a CD/DVD changer, so I am able to view DVD movies and play burned DVD audio mp3s. I guess they figure with the aux-in jack on the Tundra, you can plug-in your Ipod or other mp3 player for a music library. I must say that the process to burn an audio DVD with mp3's is time consuming. I use Audio DVD Creator. Depending on how full you make the audio DVD, it can take several hours to convert the music files and burn them to a DVD. It's usually a set it up before I go to bed thing. In the morning it'll be done. In terms of ease of use, IMO using the Ipod is much easier way to manage and access your music than using an audio DVD.I don't have an owners manual to check yet, waiting for the fall incentives!
Some aftermarket units allow you to burn MP3s to a DVD in data form and read/play it, allowing potentially thousands of songs per disk (six times more). I'm pretty sure the JBL units will handle MP3 CDs, but how about MP3 DVDs?