Well, a rally car (as opposed to a sports car) would have to have a roof, 4 doors, and tall springs for stepping over boulders. I'll give you that... the concept of a "roof" is all about safety, convenience, and so on. You might as well throw in an slushbox transmission if you're going to require a roof. Not having a roof is all about open-sky, blue-sky high dreams and freedom. That's all part of the sports car mystique. I think the Miata folks go as far to require 2 seats only, as having back seats is too practical to be a part of the definition. But then, that's their opinion. :-p

Calvin