I want to get a 1950x, as in this build - https://pcpartpicker.com/user/RainOfPain125/saved/tx82RB though I am waiting for TR4 Ryzen 2's launch
though I may way to overclock .1-.2GHz on all cores, if possible.
If I don't overclock should I bother getting a water-cooled setup? If I choose to overclock is watercooling the way to go?
What is the best air-based and water-based cooler for this?
The Noctua coolers specifically available for the platform is more then capable of cooling at stock and notching on a minor overclock. A TR4 liquid cooler will allow more headroom of course and allow things to notch a touch higher.
Though it is moot to an extent as not sure how next Gen TR will pan out. but I imagine it may be broadly similar.
Gamers Nexus did a review infact of the slightly larger Noctua cooler to the one in your list along with the TR4 Enermax 240mm cooler: https://www.gamersnexus.net/guides/3089-threadripper-cooler-comparison-full-coverage-liquid-vs-air
So your results may be a notch worse being slightly smaller and on the best end of the spectrum their is a 360mm of the enermax cooler available.