Do you actually get wet then, if it's raining and you're driving along the motorway? I have no experience of the 500C but in my Triumph TR7 you don't get wet unless you get down below about 40mph or so...
Another thing I've noticed is the speedo seems to lag behind the real speed of the car by around 4 seconds. I'm comparing the speed to a dedicated gps and TomTom.
Has anyone else noticed this?