I'm on x58 mobo with a x5675 with a h500 case. It's overclocked to 4.43ghz at 1.33 vcore (bios not load). Handles the heat fine (cpu idles at 17c and goes to 65c load on prime 95). The intake area is cramped, so static pressure fans are probably better than airflow ones. My 2 front intakes are Gentle Typhoons.
There's a long intake filter at the side of the case and also the bottom. Both can be removed (side filter you'll have to remove the whole side). I thought top fan is supposed to be exhaust? There is an included filter for that, but I don't see the point for a filter there - especially if you're running positive pressure.
I was initially worried too about the airflow, but it works perfectly fine with my old setup.