The Transporter
Premier Wheelman
EDIT: Truth is this fight would never happen. Both are pretty much the same guy. Both pure hearted, stowaways from a doomed planet, super strong aliens raised by humans since infancy, defenders of Earth. They'd probably pat each other on the back, and end up going to a China buffet. And even if they did fight, they'd be holding back, as to not destroy the Earth.
Put this into perspective:
Vegita casually firing a planet-busting blast in season 1. http://www.youtube.com/watch?v=VrStPm7zyok
Vegita's walk around power level at the time was 18,000, and 25,000 when powered up. Super Saiyan 4 Goku hits the 1 billion mark. That's enough energy output to destroy the solar system over, and over, and over again. It all depends on if Supes can take that kind of punishment.
Goku can sense powerlevels, and mask his own. He'd know where Superman is, and how powerful he is. Superman, on the other hand, wouldn't know who he was up against. How would Clark know that when Kararot points his fingers at him, he's not just being rude, he's about to blow him to Kingdom Come?
*Scenario 3 (NO ONE WINS): Goku senses Superman's power from afar, and sees that he is no match for him. Goku uses instant transmission to take them both as far from planet Earth as possible and decides to sacrifice himself up, blowing himself up and everything around him. That means goodbye to any nearbye yellow stars as well.
-And to Kal el's defense-
4. Kararot decides to show himself to Kal El. Superman decides to speed-bust Goku on sight before Goku has a chance to say "I'm Goku and I'm from Earth!"
But like I said before, these two would never fight. They are mirror images on two separate plains of reality. They would shake hands, and use the dragon balls to help eachother get back to their respective realms of existance.