SL 500 Purchase

Hello dear forum members, I’m currently browsing around at mobile something and looking for a SL 500. A facilft model from 2006 would be interesting. Now I’m falling for the different original navis have been installed. Some have the navi inside that were also installed in front of Facelift. Others have the inside that has also been installed in a 2008 model. At least it looks apparently so. I can’t imagine the two Navis installed in the same period word I have a brochure in which the new Navi is listed. By the optics the vehicle as well as the PS indication can be recognized that it is a facelift. Are the engines from 2006 already matured or should you rather choose a 2007 year? Thank you for your help Greeting Christian