A 550 is fine, even a good 500 would work well, if you have a good price on the 550 that you are happy with, get it, a little extra never hurts
Okay, thanks for the info. Just one more question, the PSU, can i bought any brand of it? Cuz all the mainstream brands are kinda expensive. Found a cheaper one, but I think that brand are made only at my country. Or this brands, FSP. Is it okay? I couldn't find FSP product at pcpartpicker.com .