The fan is 25cm, it's huge. Don't be afraid of a lot of noise though. It's rotational speed has been lowered, pretty much all you'll hear is a slight airflow. Now try to imaging how well that huge fan blows a gentle breeze over all, and thus cools down, your components.

Here we see the 25cm fan mounted onto the inside of the left case panel.

The PSU I talked about remember ... you have to mount it at the bottom front. Look where that power chord is located. Ah .. let me just grab a PSU and show you, it's much easier to explain that way.

There we go, the PSU mounted into the casing. A rather unusual place. But it saves a  lot of space making the casing really small. Heat from the PSU is exhausted at the frontside of the PC this way.