Observe this: Superman’s only advantage over Goku is the sun, and the ability to breath in outer space. In terms of output of power, speed, technique, skill….Goku FAR surpasses anything that Superman has ever been shown doing. Even tho, I DO think Superman can destroy the Earth in one strike with his body if he flew from high enough straight to the core. Now, Death Match used an unfair method of judging, putting Goku at early Saiyan saga vs Superman at the height of his power. A more fair method is here: http://www.youtube.com/watch?v=XSm_hxskoqY. This works by matching age and time of their careers. Goku can withstand twice as much as Superman, which means that dish out several times more weight of force, and can withstand more g-force, which means greater speeds enabled.
Why do I think Superman SHOULD lose, assuming Superman has infinite power from the sun. 5 reasons:
1. Superman has been shown bleeding from hits of those who are FAR FAR weaker than Goku. Which means that he can receive damage and the sun just regenerates and refuels his body. Goku should be able to pour on enough damage to kill Superman should he keep the fight on the ground. Wouldn’t take very long either. Superman’s regeneration takes time, it happens quickly, but not instantly (as indicated many times from Superman comics and films--we see the sun working on him).
Even if it were instant: If he is taking damage, it means that one strong enough attack concentrated in the right area could kill. There is no doubt in my mind that Goku has enough power in him to take Superman’s ENTIRE BODY out in one shot. Vegeta fighting Goku before Namek Saga even started, had enough power to destroy earth with a concentrated attack aimed at the Earth’s core. Goku pushed the attack back, non-Super Saiyan. SSJ Goku fighting Cell was confirmed by Cell himself to possess enough power, and plenty more left over, to blow up the planet. SSJ2 level Cell could do that, survive, and then go on to destroy the entire Universe planet after planet. What do you think Goku SSJ3 can do? SSJ4?
2. Assuming Superman is just faking effect and injury from his brutal poundings, so long as there is a MAX charge to his power-up from the sun (that is a point where his body stops taking powerups because his body can’t handle anymore). Then all Goku has to do is do what Gohan, Goten, and Trunks did to Broly (one who’s insanity and rage metaphysically provides him with power increases that seem to have no roof on it), and blast his ass into the Sun. Just like in All-Star Superman, Superman will die.
3. Assuming that Superman has no top to his power up from the sun, replenishing power instantly and eternally; Goku can blast him into the abyssal part of the ocean, keeping a stream attack like the Kamehameha wave going until Superman loses power from no sunlight and is susceptible to the attack. I would say blast him into the core of the Earth and see if that works, but I am giving Superman the benefit of the doubt here, and Goku may overdue it (still can’t breathe in space).
4. Plain and simple: Superman is TETHERED to the sun for power. Instant. Trans. Mission. Goku can literally take the sun out of the Equation, and even if Superman is totally invulnerable on Earth, Goku can take him somewhere and let him wither. I know what you are thinking: Goku can take him somewhere with a different star or no star, sure…but how would he breathe? I’m sure he can borrow a space suit (maybe Bulma’s fam--the expert on intergalactic travel and tech), or like is shown in the anime and manga: Goku can hold his breathe for a VERY LONG TIME.
If he goes full-power, instant transmissions Superman, and then starts the trademark energy barrage on the new planet they go to…Superman is toast in a manner of minutes, possibly less. Just keep him pinned with attacks that don’t destroy the planet, holds Superman down, and just one blast can kill a normal man; which Superman will be shortly. Depending on how Otherworld gets its light, a Kai planet may be an even simpler solution.
5. Finally: Spirit Bomb Fusion. I’m not talking about charging the Bomb. In the DBZ movie Super Android 13, Goku was shown absorbing the Spirit Bomb which is itself a fusion of various forms of energy from nature, to include stars…it makes sense to suspect that Goku can simply absorb the sun, he can always remake it later after he’s killed Superman.
So why do I say Goku SHOULD be able to win, but may lose where-as Cell, Gohan, Piccolo, Trunks, Vegeta…well, a LOT of people may win easily? Because Goku, although a fighting genius, lacks scientific process smarts. That much I agree with. However, I think once he realizes his attacks are having no effect at all, which I don’t think that will be the case (in which case, this list stops at #1) that sun attack has made an appearance several times in the DBZ movies. He is likely to use the instant transmission hat trick he did on Cell to blast Superman towards the sun. He will notice Superman’s power-up and move from there…or if Superman is TRULY invulnerable; he will teleport to King Kai’s, get information on Superman, and then go back and beat Superman…in other words loss by retreat, just to come back and win easily. If he is being especially retarded that day: senzu beans will see to it that he survives long enough to get his epiphany, known as common sense to many other people.