Storm would win. I am not sure why. Because on paper it should be a close fight. Where storm has a big advantage over a distance. And starfire would have a big advantage in close. But storm takes blows from superhumans like it's nothing. She gets up and just electrocutes them. I like storm, but I don't think she is super strong or invulnerable. So can anyone explain?
I say storm would win cos storms powers are a lot more versatile in a combat situation. Starfire is durable but not invulnerable so storms lightning could do some major damage. Starfire has super-strength but she can only lift ten tons which is spiderman level. Storm would own her in aerial combat. She could use hurricane winds to restrain her and then take her out swiftly with lightning.