The heat and noise are both a factor of power density, which also has an adverse effect on longevity. Home mining's biggest issue is manufacturers who think it's appropriate to stuff multiple kilowatts into a cracker box.
I am testing for noise levels today. One simple fix for pumps is to put them into a soundproof box with a pair of passive air circulation baffles, the foam is only around a $1 a square foot and the box is easy to make. I used the wall foam, 2.5" egg carton style, in my recording studio and at 2,400wrms, you couldn't hear anything in the control room, except through the control room monitor speakers. If anyone needs the design, just ask and I will draw it up and provide a public link.
There are ways to get around everything ;-) I think I am going to put these oil/water cooled heat sinks up on ebay, might as well let everyone get some since I did all the modelling and production of my own units.
Cheers