I have installed the Weathertech vent visors over the weekend, these look much better than the stick on visors like that pictured above. Also by using the Weathertech visors you can remove them later if you want without having to worry about getting all that tape off of your finish.
I'll try to get some pics this afternoon and post them. There was another thread about these a couple of weeks ago, someone was wondering about the side mirror being partially blocked by using this type. The passenger side visor very slightly protrudes into the vision of the mirror, I'll take outside and inside photos.
When installing these, I would recommend doing it in the evening. I found out that our 300C has a safety feature that makes the window go down when it meets resistance. You will have to play with the window switch to force the window to close completely. After it sits all night, the pressure of the glass on the visors helps them to seat properly. By the next morning the windows worked perfectly going up & down.