This is my make of thing http://www.thingiverse.com/thing:577557. I had the same issue as others with supports not printing at all despite using the file that has supports in the preview. I still ended up with a usable print, as you can see in the pic looking inside the back the bridging was not perfect but good enough to allow the print to finish and with a little cleanup the fan will fit fine.
I should note that I printed this in ABS with a .2mm layer height and 20% infill. I also did not have active cooling when this was printed.
Also, in case anyone has tried to install this on a Flashforge Creator Pro and had the same issue I did with the clip being too small I created a new clip that worked for me, it is located at http://www.thingiverse.com/thing:788204.