What your son is looking for is Bumblebee in Transformers. It is a Chevrolet Camaro, but it is not a convertible at all. Camaro Convertible was launched after the movie…actually a lot of people hate the idea that Bumblebee would be a convertible.
Guess your son likes this car only because he likes the transformers. If that is the case, buy this car not any other sports car to make him happy. Just drive slowly and safely in the winter and enjoy the speed in the summer.
My daughter is a big fan of Bumblebee. I still remember how excited she was when she found out Santa sent her a Bumblebee toy last Charismas. If I had money, I would definitely buy a Camaro.