Anyway to upgrade a non nav 05 STS to a stock nav system?

That's a really good question, I eagerly await a good response...

I think it can be done through GM, but I don't know for sure...

??????

my 2005 sts came with the standard bose radio,am,fm,xm and 6 disc changer. i removed it and installed a navagation system from a 2005 sts. every things works except i dont get any voice when the navagation is on.does any one know why> thank you