I bought a drop-down cooler from DangerDan and wanted to be build into the case.
After some trying and fitting I decided on installing the radiator on the lower-right side of case.

For fans I decided on 2 80x80mm 12V fans from Papst, toreduce noise I reduced the voltage to 7V.
As 2 fans bolted to the radiator directly would only cool a small part of the radiator dirctly beneath the propellors, I created a shroud made of see-through plastic and installed the fans so they sucked the air over the radiator an blew it out of the case (see pictures below).
This ensured all the area of the radiator would be cooled actively by the propellors.

After having assemled the radiator, fans and shroud, I made the holes in the side of the case so the whole assembly could be attached to it (see pictures below).

Next: The Diffusor