Just bought a used, 2007 model and noticed the maps were very old. Did numerous searches and some would yield info on how to remove the old DVD, where to buy the new one.,etc. I will summarize what I've done:
1) Found a user on EBay selling nav maps for all types of cars. Bought a 2013 map for my car for $24.95! Don't even ask what the dealer wanted.
2) Turn the car on. Pop the faceplate off (the part that says Lexus) by pushing up. It should come right off.
3) Select MENU - Eject DVD
4) Old DVD comes out and insert the new one! (My Nav DVD had a 2006 date. Very old obviously)
5) System will update and bam you have updated maps!
$25 bucks vs. $350 + from the stealer/dealer...
Questions, hit me up!
Thanks