Originally posted by: Jeff7
	
	
		
		
			Originally posted by: Son of a N00b
If its not broke dont fix it!
unless you know what you are doing, playing around with a PSU can be very dangerous...do you know how to drain the transistors?
		
		
	 
Oh the irony simply oozes from that post. 
 
That kind of fan guard really doesn't block air much. The guards are made of bend cylinders - cylinders aren't good at blocking airflow. The air flows right around the surface, rejoins at the other side with a little bit of turbulence and keeps on going.
Stamped fan guards 
http://www.directron.com/rs380pmsr.html can block some airflow because they have flat sides - air smacks right into it. Those can be sliced out and replaced with wire fan grilles such as are on your current power suppy. But again, that requires opening up the power supply, which can be quite dangerous.
Summary - those fan grilles are fine, and add very little restriction to airflow. Leave them in. Unprotected fans aren't a good idea. You may think you'll never get a finger near there, but the first time you bump against that fan guard, you'll be glad it's there.