Finally got to see a factory NAV unit in a DC yesterday, but the XM wasn't activated. My question for anyone who has this combination: when you have XM on, exactly what is displayed and does it use the whole screen of the NAV unit? I had an aftermarket Sirius in my F250 which was great; three lines of data and continuous scrolling of channel, artist and song title. My '06 Silverado factory XM has one (incomplete) line of text and I can't figure out how to make it scroll at all. My wife's A6 switches between radio display and NAV, giving the same amount of info my old unit did in the F250. Does the Tundra display work the same way? Thanks.