Replacing factory radio with factory navi. Will it Work?
 

I have a 2005 Sts with the factory radio still installed. I orginally wanted to install a pioneer in-dash navi unit but crutchfield says it doesnt fit. So i was searching on ebay and found a factory navi unit removed from a 2006 STS. .I was wondering if i could take out the factory radio of an 05 and have the factory navi unit of a 06 put in its place will this work?? I know that one is a 2006 unit and the other is a 2005 i beleive the new style radios and navi's didnt take place till 07. So i am assuming that the navi unit that would of came in my car of an 05 if i had purchased an sts with navi would be the same exact unit of an 06. Am i right or wrong on assuming that they ar the same till 07?