If you dont follow EULA rules, your skin will shrink up plus your brain will explode. Just maybe the FBI will kick your door down, lol. All you need is 8gb. But you can go for 16 if you wish. But 32 is overkill.
dual video cards can be better than one, assuming the game supports it. Though most of the time 1 more powerful card will be faster and cheaper than 2 lower ones. Liquid cooling is only necessary if you absolutely want to push it as far as you can go with overclocking. If your just going to 4 ish GHz then air will do it as good as water.
its actually a pretty good match.