Upgrade radio and still receive Turn-by-turn directions

[TonyMazz]

I currently have factory UUI AM/FM radio with CD with On-Star and can get directions displayed on my radio display.

 

Is there any non-GM radio/stereo head units that can interface with On-Star and allow the same directional display... ?

 

 

[crewl1]

If this was the case I would suspect you could get that info from the OnStar website, but they only talk about GM vehicle factory system compatibility.