Oh, Really, nobody can help in this situation. I want to replace my radio(Which also is used in opel) on Navigation System. In Russia,Moscow dealers know nothing about it.Because it is not delivered on the Russian market. And ONLY YOU Americans can help me!!! Friends! For whom it is not difficult please Whether learn from the dealers if it possible to change on NAV if YES then that for this purpose is necessary? Thank You ,Stanislav from Moscow,Russia!!