Having spent a lot of time in Germany and 20 laps or so at Nurburgring, I know the German car nuts watch what's happening on the track carefully. I can just imagine them saying, "Ach du liebe, so schnell, ist das Americanische Camaro! Was denks du, es is mere scheller den eine Porsche, GTR?!!".
There are spots around the outside of the track where the general public can watch whatever goes by, but they can only see it for the few seconds in view. These videos were most definitely not GM shots.
Do you think GM wants this car to beat the ZL1? If so, I'm pretty sure it would mean the early demise of the Supercharged Z. I'm definitely hoping it's within my means to buy at some point in time...I know I could never afford a new one, so I'm gonna wait til one of you guys decides they want a 6th gen and I will get your Z28!