stefuel

In my quest to find a 2006-2008 Z06, I found a few but passed on them because they didn't have the factory nav. Then I read someplace that it was no big deal to install it and mostly plug and play. If you have a 2006 you need a unit from a 05-06 to work? I have seen them here in the for sale section with discs and ant. for about $400.00 If all of this is true then I don't have to ignore some potentially nice cars in the quest.
Thanks,

Chip