I posted a while ago regarding the mirror blinker. On a ford parts website, link attached, it looks like you can order the bottom blinker and puddle lamp as one part for about $35 per mirror. I'm looking to do it myself, am not sure if wiring exists or you have to add. In any case, whatever route you go , navi mirrors or replace with this part, if the wiring is not there, you still have to wire. This seems a whole lot cheaper and not as much hassle as replacing the whole mirror.
http://www.trademotion.com/partloca...=2003&graphicID=MC03710&callout=4&catalogid=2
it's a long link, you may have to cut and paste. If anyone has done this, I'd like to know.