Just seen the vid, that's a nice looking car. The people who replied obviously don't have a clue what their talking about. Okey, the speed, anybody knows that concepts are one of a kind cars, not many spare parts, ect, like the Camaro Concept, that's why they don't drive them very fast. The sound, that's easy enough. One of the people said that they have them and their so quiet that people walk out in front of them(guess people over there don't look where they walk), maybe GM made it so people would hear it and not walk out in front of it(safety feature).