A. the CPU cooler fan can run quite slow, if you use a large enough heatsink. a good allround cooler is the volcano 9, or something else that takes the 80mm smartfan2. it has temp control, thats quite useful.
regarding intake and exhaust fans, you can get away with suprisingly little if the case is a good one and is well designed.
one medium to slow rear fan can be enough if no overclocking is planned.
the most effective place for a single fan is at the back, below the PSU, venting warm air from around the CPU.
usually 2 fans is sufficient, one front suckin in and one rear blowing out (ignoring the psu fans)
and yes, balance the fans... just get two of the same speed.
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Aluminum means nothing, it's all about quality design. I have GATEWAY cases that have a SUPURB design for the integrated fan grille, and some "name brand" cases that don't! There are a lot of cheap aluminum cases out there, some of them are expensive at certain vendors, yet maintain the low quality design. No use in getting an expensive aluminum case just to get good fan grills when a good quality steel case can be had with similar grille design at lower cost.
Oh, and my Dell/Micron/etc Palo Alto (plastic) cases have almost no restriction in the fan grille, the grille is almost a wide mesh (my gateway cases have sturdier grilles that still offer good flow).
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