I have pimped up the Apollo with lots of heatsinks to reduce the noise further (fan runs below 1620rpm at 30 degrees C ambient) and I run it without the case. As a minimum I suggest adding a heatsink to the R44 power converter at it is quite hot (>60 degrees C).
https://imgur.com/a/SB6A4puI use the following heatsinks:
20 off 20x20x10mm
11 off 8x30x8mm
2 off 6x4x4mm
1 off 14x14x5mm
The 8x30x8mm heatsinks probably help cool the Apollo down the most as they are at the base of the main heatsink.
Smaller 20x20x5mm heatsinks would probably work just as well and be cheaper at the top of the main heatsink by the fan.
R44 is the inductor to the main power stage. This is designed to run a 90C+ ...60C for this part of the power stage is pretty cool. There is no need to put heatsinks on it, if anything the smaller heatsink right behind it probably helps the most, since thats the main MOSFET block and produces the most heat. These are rated for 125C but cooling them down helps with power efficiency and longevity of the mosfets..but again this is not needed.