Thanks I really like the apple carplay I will look into units with thatI think you're thinking 'almost' right. These days, you don't even need to shell out for dedicated navigation - get yourself something that supports Apple CarPlay or Android Auto, and you can use Google Maps, Waze, etc., for navigation. Plus you have the integration for phone, apps, music, etc.
If you really want the on-board Navi, NavTeq (aka: 'Here') was generally regarded to have the best / most accurate maps, so look for a unit that has that over TeleAtlas (TomTom)
If you want a 'factory' look, keep in mind that the GM deck requires you to keep the Navi disc in the unit while using navigation. You can imagine how that eventually works out.