My girlfriend wants to get a used Tahoe and her primary wish is for it to have navi. Problem is, she really can't afford the LT2 or LTZ models that come with that. I'm trying to find out if we get her one without it, how hard is it to put in and which year/options would make it the easiest?

For example 2007 seems to need the Bose and GPS antenna.

Are there any requirements for 2010-2011? or the 2012?