Replacing factory radio with factory NAVI

[MCAT069]

I bought a '12 Z71 yesterday with the basic single CD, XM radio. I worked into the deal that the dealer would install the factory duel headrest DVD players. I want to put in the nav head unit. Anyone know the part number off the top of their head? Also, anyone have any experience with the Alpine redesigned units? I was leaning towards it if I could not get a factory nav just because the Alpine looks factory.