Huh, I guess my reply got eaten. Here goes again...
your fan swap will do nothing to change the speed-up-and-stay-there behavior
I was either going to use a fan with it's own thermal control (i.e. a Verax or those Papst w/thermal control on Silicon Acoustics) or just use a fixed-speed fan. My dilemma is I don't want to use a fan that's too little CFM and fry the PS prematurely; it's a great PS otherwise.
If I were you I'd play it safely and just put the PAPST in there. It will probably move more air then the standard fan and is pretty darn certainly a lot more quiet.
Is it enough CFM? A Papst NGL is 19CFM. I guess I'll have to look up the specs and see.
I have a coolermaster 110, and the air coming out of the top blowhole feels really cool, so I was considering just taking that fan and putting it in the PS, and leaving the top vent sans fan. I have access to some tools and a workspace now, so I was going to duct the CPU to the back fan hole just below the PS, making the PS the main vent for system heat. Since the CPU is the hottest thing in there, it shouldn't affect ambient too much.
I can't think of any reason why not to do the mesh, but I can't think of any reason why *to* do it either!
I'll do it because I can
No, really, I've already twisted the vent fins 90 degrees to increase airflow, but it looks ghetto and doesn't look like it opened it up much. If I use some bolts and a bit of epoxy I can open up that entire back area to allow more airflow and stilll keep it more structurally sound.