Retrofit RNS-D to Pre-facelift

First of all, I would like to know if this is reasonabley possible, and what parts and work is required. I'm asking for RNS-D because I get the feeling they are a bit cheaper, easier to come by and less hassle to install.

Ideally I would TV + GPS, as the current stock CD changer will only work with pressed CD's and not burnt ones. I am trying to keep the stock look and retain the Bose element if possible whilst getting some more toys!

Thanks