toby - as kusojiji said, it's essentially for better airflow. The main reason I had it was to have an almost vacuum effect in the rad area. The tubing will go through that wall too, so we'll have to seal those parts as well.
The PSU is a mini-ATX to allow for more space and it will mount like a PSU in a usual case.
kusojiji - my Taekwon Do instructor is a plumber so I asked him about them yesterday and he told me to check out a store near by. Quite handy
If you look at my new design below I only have the extra fan on top. I'm gonna keep the shroud because it will be sealed and suck air through the radiator and can afford to be higher speed than the exhaust fan. Also, cause Gavin made it for me for free and I don't wanna hurt his feelings by not using it
P.S. I'm gonna have a window the the side facing (the box will be at my feet at a 90 degree angle to my case, lengthways) and some cathodes so it looks good. Also, gonna have a relay in the case connected to the PSU to turn on with my computer. Will then get some larger tubing (like that on washing machines I think) to cover the water hose and the relay connection, just to tidy things up