Personally I would suggest water cooling @ 4.5ghz but if you were going to have air cooling I would suggest only one but costly air cooler. The Noctua NH-D14 Dual Radiator CPU Cooler.
Overclocking past 4.2ghz won't really be necessary but it's your choice. I settled with 4ghz with cool and quiet enabled for every day use.
Don't forget to turn of the turbo core feature in the bios.
if you have any further questions feel free to ask
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