So something like Corsair Enthusiast Series TX650 V2 is better? There is no corsair 550w in the place i am buying so i guess i can get this one?
About overclocking i dont know... I'm not used to do it and all i hear is that is decreases the lifetime of the hardware so... Should i think on doing it? Im planning on gamming several hours in a row with this so...
There's always a risk with overclocking. Albeit a low one as long as you follow instructions. You can buy the i5 3570k and if you decide you want to overclock later... you can. However the non K series is cheaper and will suite you just fine.
If you could post a link to the corsair PSU. Yes that would be much better.
http://www.corsair.com/power-supply-units/tx-series-power-supply-units/enthusiast-series-tx650-v2-80-plus-bronze-certified-650-watt-high-performance-power-supply.html
talking about this one
That's a good psu and should be enough if you want to go SLI/crossfire. However strife_ff7 has suggested a good one that's much cheaper.