Interesting thread. I don't see any issues with putting them in the garage. The operating temperatures of the computers should keep them dry. I would place them in an enclosure of some kind. Maybe a cabinet with a temperature controlled damper. You can find these that are totally mechanical and quite inexpensive. Also maybe a switch and a filtered fan to work in conjunction with the damper to circulate air through the cabinet if the temperature rises far enough. I work for a major manufacturer and have seen systems running reliably for years in environments that you wouldn't believe! Good Luck and let us know what you decide.