I see this post is quite old, but let me ask the following: I have seen the sat nav of my 4200 is quite old, there are some roads that are not recognized. Also, the interface with the user is not top notch. I am used to TomTom, and the most recent sat navs of TomTom are great. So, I buying a TomTom seems to make sense.
However, I would like to keep the car as original as possible. As a consequence, I have thought about the possibility of updating the original sat nav. Has anybody done that? With the new CD, is the sat nav useful for normal life?