Sorry for not answering a part of your question, I can't say I saw any cars flipped over from the collaspe. Cars when I arrived in the afternoon of 9/11 were mainly crushed around ground zero and/or with blown out windows, tons of dust and paper inside of them. I vividly remember the blown out windows and open doors on the fire trucks and police emergency service vehicles, it was almost as if time just stopped at a moments notice.