Hmm.
Interesting that the CPU thermal throttled on such a modest overclock (for that chip). What voltage was used to get your 4.9GHz? Granted, it's only cooled by a 212X, but that's pretty much a nothing overclock in my opinion - 200MHz on all cores is very little. In fact, it's little enough that I question why your review states it's an "aggressive" overclock.
For comparison's sake btw, 100% of 8700K's Siliconlottery tested, would reach 4.9GHz at 1.387V with a -2 AVX offset. 6% of chips tested would reach 5.3GHz at 1.437V. I'm quite sure the *majority* of 8700Ks will reach 4.9GHz at below 1.3V.
Also surprising that adding two entire fans did so little to affect the temps. Just goes to show how airflow-constrained some case designs are even when fully populated with fans - especially considering you were using 3x static pressure optimised fans and 2x "balanced" pressure fans.
All of this is another good reason Darksaber should be testing this sort of stuff - Even in a tiny chassis like this, when you're using 3 120mm fans in a space that small, while using a not-excessive, but certainly quite capable, CPU cooler, it should be possible to gain 200Mhz without thermal throttling. If your methodology is flawed, then Darksaber bothering to test thermals, even if his data is also flawed, would at least provide another point of comparison instead of dooming us to believe this case is a chip-cooker.
As is, we have little to go on other than your data, which paints a terrible picture of this case.
I would seriously question why TPU considers this case "Highly Recommended" in light of the new info you've provided - and that's even overlooking the standoff issue you encountered, which I *really* hope is a case of lost-in-translation between you and Silverstone.