If I plan to overclock the card anyway, which card would be better?
If I overclock the already superclocked card, is it still covered under warranty?
Anything else I should know about the differences between these two cards?
I'm going to say the Superclocked cards have components that passed a higher level of quality control. They want to guarantee that they can handle the more demanding conditions. In fact, I bet the chips that don't pass the stress test go into the non-SC versions.