I will second the comment that the windows have to be up for any of these devices to reduce turbulence. I also will not drive with the windows up if the top is down, so I get no benefit from one.
I don't understand the "Saturn Approved" or GM Licensed statements since, as far as I know, GM had nothing to do with any of the stick-on wind deflectors. The GM version required that brackets be mounted to the top of the tulip panel (the silver painted curvy part) and are referred to as "fly swatters". I'm sure that a dealer somewhere installed one of these, but I don't think it was very common.
All that said, the one you picked is the better of the two options in my opinion, since the one that goes into the trunk can require adjustment to the trunk lid.
Sky NA 2007 Midnight Blue
Sky RL 2008 Carbon Flash - Naked