When I was in high school I was in a class where we learned about technology, especially green technology, and we made an electric car. It was a one passenger car and we raced it against electric cars from other schools. It's been two years since then and I was thinking of doing it again on my own except making it a two passenger car but I don't know what size tubing I should use. We used aluminum tubing to lessen the weight and used tig welding for the frame. I love to tig weld but I don't know if its absolutely necessary for a car frame. Any suggestions for tubing size and welding processes and feedback or other comments would be greatly appreciated, thanks in advance.