I upgraded my 1000W to a 1300W EVGA PSU in preparation for the KPE. I’m sure that I would have been technically safe with 1000W, but having the extra headroom gives me some peace of mind and will hopefully allow me to upgrade my 9900KS to a future more power hungry Intel CPU in a couple of years without having to buy another PSU. I’m currently running the 9900KS at 5.3 on all cores, so it pulls significant power by itself.
I agree that 1600W is overkill for a single KPE, particularly if you’re not doing extreme LN2 overclocking a la Steve and Jay style.