Unfortunately the cooling wasn't as effective as I had hoped. With the big dust filter on the back and the loonies at 5v the system (motherboard temp, not cpu) would eventually overheat and crash. Same at 7v. Without the filter at 7v it works perfectly. I am looking for a less restrictive filter, maybe I'll use some mesh like some antec cases have.
Some extra notes: the PSU's fan has been removed, it gets enough airflow from the 12cm fan in it's "tunnel". I have added a fanmate on the cpu fan, and it's turned down to minimum (~1200rpm).
The stock CPU fan is the noisiest component in my system, possibly because it is not soft-mounted and so it is amplified a lot. At the same speed it seems louder than in my previous case
, but the rest of the case is quieter, so it's probably just an impression. When I'm feeling generous towards myself I'll buy a ninja.
I can't hear the case fans, and I don't think I can hear the Arctic-Cooling Silencer, but that'll be the next problem once I get a ninja.
I don't hear the idle noise of my WD5000KS, I can still just hear the seek noise that doesn't really bother me.
All in all it is a success: I have a quieter computer than before, but I can still hear it when the ambient noise gets low at night, so there's still room for modding