The cable management is quite good I think, as long as your PSU 24 pin cable is long enough to go around the back of the case and through an opening into the motherboard. The bottom fan is quite useless anyways and should be moved to the front of the case, right in front of the middle HDD cage.

And about the door, a friend of mine has the P180 and his door is broken, my P182 door seems quite stable for now. Antec used plastic hinges though, so I wouldn't try to do any major stress testing on it.

The window can be done yourself, I made one last week. I'm quite happy with it, you just need some time and a jigsaw. You can also use some rubber edging to make it smoother. There's a thread in the liquid cooling section about it.