Customized computer?

[Buffalobiian]

Although this might intake some of the PSU's ventilated heat at the rear of the case where it drifts up.

That should be minimal. Good quality, efficient PSUs these days barely have to spin during normal use, and the air blown out during load isn't anywhere close to hot (from memory).

I could make the rear the outtake and the top-rear another intake. Hmmm. It will be an easier decision once I have the case and the fans all in front of me.

Having a top-intake might drawn in more dust, but that's just myself thinking. It might not actually draw in any more than a rear exhaust would. At the same time, a top-intake might also extend the fan's life if it's a sleeve-bearing type. Mounting sleeve-bearings into top-blowing position stresses the fans since the blades plus gravity combine together into a downward vector, pulling the fan from the rest of the mount.

^ That's the theory anyway. All I've actually confirmed myself is that there's a clicking noise to be heard when I mount mine horizontally like that.

Regarding the airflow Raven, you can actually try that config without turning on one of the rear intake fans (with your fan controller) to see if the extra fan even has an effect, or even a counter-productive effect. Sometimes just having the vent open for air is enough to deal with any intake-bottlenecks without the potential to stall airflow like Ani was worried about.