is EVGA GTX 560 Superclocked already maximum Overclocked ?

Yes, factory overclocked cards have already already been overclocked as far as they're likely to remain stable. They do NOT provide a higher baseline to start from, they just save you the trouble of OC'ing yourself.

You might be able to push it a *little* farther, but not much. However the previous poster is right about no two cards having exactly the same maximum overclock- it's just like CPUs.

Of course you're better off getting a stock GTX 560 Ti and overclocking that yourself, instead of getting an overclocked GTX 560 (non-Ti)

No.

there is no such thing as a factory sold overclock. overclocked is what you run the card ABOVE what the factory sends it at.

also, no two cards will ever overclock the same. there are general ideas of limits and maxes, but each card overclocks more or less, same as with processors.

how much more you can overclock those until they 'max their overclock' is determined by how far they will go. could be 10mhz, could be 100, could be more. all depends on the card, and is no way to know just how much more u can overclock without testing.