Pioneer AVIC N series navigation units

Has anyone had experience with any of the Pioneer AVIC N1,2, ect. navigation units? Do they come with, or can you download topographical maps to them?

i have the n2... got it mostly for the xm navtraffic since i live in the LA area and pretty much all of the highways r integrated with the speed sensors... the maps are loaded onto 2 dvds... 1 dvd for western half and 1 dvd for eastern half... i duno anything about topographical maps tho...