No NDA signed. And the agreement to me at least was that if I wanted a replacement, I had to mark the box and the bottom side of the car in a silver sharpie to indicate it was a rejected test sample. At the time of writing this I already saw someone on a BST group selling their test sample and I know of another youtuber who sold his also. Keeping it or selling it wasn't discussed but since I and others could keep the test car I assumed anyone could do what they want with it since a replacement was on the way.