You will be wasting your money.
14nm skylake runs cool and does not need exotic cooling.
A simple tower type air cooler with a 120 or 140mm fan will do the job.
I get to 4.8 with a noctua NH-U12s
FWIW:
As of 5/2016
What percent can get an overclock at a somewhat sane 1.40v Vcore.
I7-6700K
4.9 2%
4.8 17%
4.7 59%
4.6 93%
4.5 100%
I5-6600K
5.0 2%
4.9 11%
4.8 36%
4.7 64%
4.6 88%