So I have two Macintosh SEs, one I keep in its original condition (20MB hard drive loud fan etc)  The other one is my play Mac which I upgraded with more RAM, Hard Drive etc.  My most recent addition is an ultra quiet fan. 

Now I went for a 40mm fan because this particular SE does not have allot of room inside (it had the vertical hamster wheel fan).  So far my tests have shown it to be sufficient.  I open it up after some use and check the temperature of various components etc.  

However I can probably fit in a 60mm fan inside if I want to.  My question is, has anyone else done this to a SE, and what was your experience.