It is an unlocked processor, so overclocking won't be a problem. I'm not exactly sure what you're asking, though. The 2500k is now 2 generations old, so if you're building a new computer the 4670k is the current generations equivalent of that processor.
The 2500K is still a very good cpu with great OC potential. The newer cpus will not likely OC as well but they are more efficient clock-for-clock. That being said, in games, if that is your primary function, little benefit will be realized.
-Bruce
I wouldnt bother upgrading from the 2500k for gaming yet. Personally im waiting for the next generation to see what improvements will come. Its only a matter of time before Intel release 6-8 core CPUs in the mainstream desktop (ie. not high end socket 2011)