Yes, riding the spoiler in the fore or aft positions do make a very big difference I have found. I like it because it is very quick and simple to move the position of the screen. So, it's hot, your offroad ? Down she goes, on the way home it's raining or cold ? Up and foward it goes.
I tested mine with an Arai XD which is notoriously noisey and sensitive to the wind.
Again, is it an overpriced piece ? Hell ya, TT has some nerve, but does it do the trick ? Yep. Drink a 12 pack, wait 15 minutes for it to fully kick in, then push the "BUY" button.