The super cup is nice but it will not seal tight and the RD wiggles or bounces a lot.
The hotter out it gets the worse it is. As I am driving down the road it will wiggle and the display will be facing you. Smooth road or not it is the same.
If it is really cold out it is somewhat still.
I have tried to put it on several times to get a good seal so there is no space between the plastic and the rubber cup with no good results.
Here is a vid of the problem.
[ame=http://s255.photobucket.com/albums/hh135/vger_1701/?action=view¤t=supercupvid.flv]Super CUp video by vger_1701 - Photobucket[/ame]