well it all boils down to how much are you willing to spend and what looks good and fits to your build. Here are teh popular high end ones currently among z370 builders but im sure there are a couple more to add on the list. the bad thing about 1.5Kg heat sinks on air is that it will break you mobo if you move your case alot of you suddenly drop your case with some force but should be generally okay if you dont move it too much. as for water coolers, the corsair ones (esp the i v2 series) are pretty reliable despite people complaining about leaks and weird pump noises coming from their system. if by some off chance you get a defective one, corsair has a very good warranty and support for you to get a replacement. generally, air coolers...