Update on the i9-9900k build I'm making for a customer. Pictures below. I have Noctua-ed all the things as you can tell. The only problem I have currently is getting the 120mm fan adapter to stay affixed to the C7 Cu. My solution to this will be epoxying two of the 120mm fan holes on top of the 92mm adapter.
At idle it's extremely quiet. During load it gets noisy (tolerable) and depending on how many threads are in use it can actually get quite loud (2 threads are worse than 16 threads). This is because I set the thermal power limit for the CPU on the motherboard to 95W short-term and long-term. This usually means when all 16-threads are in use (Prime95) the CPU throttles back down to 3.6-3.7Ghz on all cores. With 2 cores, it can sustain 4.8-5.0Ghz.