As well as the dimensions you really need to think hard about orientation of the components and how you will deal with the system taking air in and pushing it out.
The Cube can turn into a real hot box as the usual inlet for air is the bottom (generally a difficult route in) and then out of the top.
you not only have to fit components that match this configuration - unless you are cutting the case at the back - but make sure you leave clear space for that air to follow the chosen path.
if you choose that PSU where will you put it, how will it get the air it needs and where will it throw the heat back out. Also of course as well as expelling air the case will radiate heat so how are you going to stop that from pushing up the temperatures of everything else in the case?
That cooling system you linked looks to be discontinued. Plus, if you are going for a closed loop system bear in mind you will need to cut it as the pipes will be far too long. Cutting it means you then need to drain it, re-fill it and bleed it....and closed loop radiators never seem to have any convenient mechanism to allow you to bleed them. I would seriously recommend the radiator I am using as it copes really well with the heat from my 3770K - even over clocked and without a reservoir.
