I have a few questions:
How noisy are the fan?
How hot do they get? - do fan need to run at full speed? If not overcloking and running scrypt only
If you have a lot then it gets NOISY.... I have 2 and on one the fan made a lot of noise, i cutted it out and inserted a new 80mm fan. Now it is silent and works great.
As someone already said, if it is for scrypt only you don't need then fan and it gets only warm to the touch... for SHA you have to have the fan..
regards,
P.