Watching him peel the adhesive off the backplate made me cringe a little bit. I'm sure it's perfectly safe, but I can't stand having to force anything (especially so close to the CPU socket)!
Seconding what others have said; with your AIO cooler, you'll be able to hit 4.5 GHz easily, even if you didn't win the silicon lottery. You'll likely be able to overclock higher than that. Plenty of people hit 5.0, and most people seem to settle in around 4.7-4.8 stable.
Really like the build btw. +1!
This build has a 550 Watt PSU for a ~400 Watt system. That's more than enough headroom for overclocking both CPU and GPU, although the difference in price here isn't enough to justify skimping. If you want to spend another 20 bucks for a bit more headroom, that's fine, but it's really not necessary. I wouldn't recommend SLI to anyone at this point, but if you really feel the need for that kind of expansion, 750 Watts is probably best (that puts our system TDP at around 580 Watts, so 750 still gives enough headroom for overclocking, while 650 might be cutting it close).
and m.2 drive to avoid any extra cables in a small case.
Interesting that the label is upside down on the only side not covered by the shroud; I guess that's intended for cases with the PSU at the top?
Great looking build. Did you install the PSU upside down though?