[sdecoman]

I am still near the bottom of the learning curve when it comes to aerodynamics but let me say this. With the spoiler on, if the road or street is wet, that back window becomes totally unusable within seconds. It happens each and every time whether it is windy or not.
I would seem to a newbie like me that there is quite a bit of turbulence back there that pulls the air right to the rear window from the rear tire spray and from behind the car and deposits all the dirt there. If I'm wrong that's ok, but I need to here why that's a good thing not just reference to a manufacturer's video which as we all know can be made to show what ever they want.
I could do a tuft test once I get a video camera which until now was an unnecessary expense. Until I can come up with a solution that is better than the what I had, it makes no sense to me to put it back on unless I fill in the gap between roof and the spoiler as at least a test. The holes to mount it are still there and the third eye can mount anywhere.
By the way, as an off-subject question but peripheral to aerodynamics, can anyone point me to a digital video camera that they would recommend. Image stabilization I would think would be a key feature for this kind of work.
Anyways, thanks to all who have replied. If I can't take criticism, I shouldn't ask for comments.

Tom Beno, a South Dakota ecomodder that actually believes that what we are doing here is more important than the stares and derisive comments people will make as they pass you in their gas sucking SUV. You all have just a great day.