Hello, I know that there are some topics already. However, in this case it is a different starting point. It is a Smart 451 with the “old” dashboard. see link:http://data.motor-talk.de/…/smart-armaturenbrett.jpg I have an original Smart Radio Highline Navi but this is only REIN the Navi (see picture in the appendix) without the round aperture. Now it would have to be possible to upgrade the Navi? I would then only order the DoubleDIN mounting kit. see link:http://www.ebay.de/…/151306026605?_trksid=p2054897.l4275 The Navi no longer differs from the dimensions to a retrofit DoubleDIN Navi like e.g.Alpine, JVC…. or is this NOT true???