Okay, was gone for a few hours. The comic in question was from a good long time ago, and had a depowered superman losing a boxing match. Don't remember too many details beyond that, like I said this was from awhile ago.
Also, to touch on something earlier. While Goku being a galaxy buster is based on speculation, being a sun buster is entirely cannon. While many people dismiss this as a boast, Cell states near the end of his story arc that with his Ki he can now destroy whole star systems. This is later confirmed by Akira Toriyama in supplimentary material. Specifically, it is confirmed that Cell can destroy stars using a fully powered Kamahaaha.
Almost immediately after this statement is made Cell gets into an energy blast dual with Gohan, who had recently ascended to Super Saiyen 2. During this dual, in which both parties are going all out and both are using a Kamahaaha, they are shown to both be roughly equal, with Gohan attack eventually being able to overpower Cell.
Now, yes this is Gohan, but it is also only Super Saiyan 2. Even if Goku couldn't match the same feat in Super Saiyan 2 as well the Ki multiplication effect of transforming into Super Saiyan 3 would easily get him there, and that's not even getting into the Super Saiyan God multiplier.
So again, Goku being a star buster is a safe bet. You'd be pretty hard pressed to find a reason why Gohan could do this in SS2 form, and Goku couldn't in SSG form.
This is why Superman casually stepping through Goku's Kamahaaha bothered me so much. The amount of force necessary to destroy a star is utterly massive, and even Superman would have to feel that somewhat. Granted, with all the eye rolling feats under Supermans belt he still likely to win a match-up, buts he would probably have to work at it a bit.