The short answer is no. No build actually needs liquid anything.
I personally have better experiences with air coolers than I do with closed loop coolers. This includes temps and ease of use.
I wouldn't worry too much about getting to 4ghz. You will most likely get slightly higher clocks than that with ease.
I personally have not used that cooler nor have I ever even seen it in person so I can not comment on it specifically. The 6600k does not really have a problem hitting 4.2ghz+ in most cases though.
The short answer is no. No build actually needs liquid anything.
I personally have better experiences with air coolers than I do with closed loop coolers. This includes temps and ease of use.
I wouldn't worry too much about getting to 4ghz. You will most likely get slightly higher clocks than that with ease.
I personally have not used that cooler nor have I ever even seen it in person so I can not comment on it specifically. The 6600k does not really have a problem hitting 4.2ghz+ in most cases though.