The slightly more silent Ender 5 Plus (#E20F3)
Well, since the printer is running just fine, I used it to make some quality-of-life upgrades to it.
The bottom lid that covers PSU, all the mains wiring and the rest of the electronics has been removed and replaced by a 2 part print (due to size). Several reasons for that: a) Four of the six screws are covered by the additional aluminium frame, so it’s difficult to remove if properly fastened, b) if left unscrewed (which isn’t much of a load problem on the remaining two screws since it is sandwiched anyway), the ends of the large metal piece would be free to vibrate and resonate, c) the stock 40mm fan close to the driver board is terribly noisy and pointless in terms of air throughput, so I would have swapped it anyway.
So the new lid does have a cutout for a 120mm 24V fan (Sunon MEC0252V3-A99) which is currently put in series with a 220R resistor. By doing that, it runs at roughly half power and is basically inaudible, plus has way more airflow than the previous fan. The lid part carrying the fan is flush with the case, and the other part is flush most of the way as well, plus a little overlap around the center screws. A mere 300ish 5mm holes should also provide enough cooling. Both parts are mounted directly onto the new 80×40 extrusion frame by two M5 nuts – design was already perfected with the LED mounts that sit outside, I just needed to insert the heavy nuts into the frame without the entire thing bending to a saddle configuration again. (~0.5-1mm/m, so not terribly warped…)
After that, and before printing a couple TPU suppositories for work, I tried the TPU material with some test prints for the motor mounts. Just a simple 1mm spacer between frame and motor, shaped like the NEMA 17 mount itself, and usually available on AliExpress for like a dollar per pack of two – but you know, shipping cost, shipping time, and the urge to try that TPU 
Anyhow, those dampers in TPU offer little to none advantage, so I wouldn’t recommend buying those made from silicone, they are probably just as useless. But they have no adverse effects, so I will not put in the effort in removing them again…
…plus I almost killed one of the motors on installation of these, because the threads were already damaged by the previous owner, and I finished them. Too bad it cannot be drilled to M4, as the magnetic steel core material is very hard to drill and tends to delaminate, so I needed to use long M3 screws and a nut on the top – thankfully provided by Creality, as those M3x40 of the silly motor/gear shroud are just the perfect size for the job.
And, well, the DC-DC converter for the lights also got a suitable connector with pin pitch 7.5mm (80V max, jeez!) that can now fit the 3mm² ferrules properly and is also detachable. It still needs to be mounted to the printer, which should be an easy task and is one of the top priorities next week. Still undecided if power should come from the existing 500W/24V MeanWell power supply (which doesn’t have enough headroom during prints), or if an external power brick (20V laptop supply?) would be a better idea.
