I'm planning on building a pc in a H440. I plan on using a kraken x41 to cool the cpu mounted to the back. I was wondering how I should set up the case fans, toying with the idea of 6 intakes. Would this be a good idea? I know I want positive pressure and having the 6 intakes would allow me to run the fans at a lower rpm, I'm just not sure whether it's a good idea.
The three standard front fans at low speed would be enough intake for most builds. There's no need in general to have more than just a little bit of positive pressure.
One thing you would do well to have a look at would be to tape up the excess venting at the rear exhaust after the radiator is mounted. Since the vent is much taller than a 140 cooler there will otherwise be an unwanted re-circulation of air in that area.
Not entirely sure that is needed... After all he have 3 intakes and only one exhaust out of the box... Even if he doesn't add more fans, this is quite a positive pressure. And the path of least resistance is exactly thru those open vents.