I wanted something to cool the plastic as it comes out of the nozzle but didn't want it to be bulky since my printers is somewhat small and didn't want to make the usable volume even smaller. So I replaced the stock piece with my own and the stock fan with a 40mm one. Basically it's the stock piece but at the bottom air is directed towards the nozzle.
Note: I have my fan set at 60% for perimeters and 30% for infill at 80% or so, depending on the fan, the hotend can be cooled so much that it won't be able to reach the temperature you want.
Step 1: Printing
The settings I uses were
Printer Brand: Solidoodle
Printer: Solidoodle 2 - Expert
Rafts: Doesn't Matter
Notes: Use whatever setting you normally do but make sure to use support unless you can bridge about 40mm.
Download the file here or from thingiverse: http://www.thingiverse.com/thing:1623085
Step 2: Almost Done
Remove the support and screw a fan onto it, flip it upside down, then it snap it on the hotend, mine two fins from the top. Then start printing with higher overhangs etc.