In reply to your first question, my answer would be "Sure, but you'd better make sure it's a damned good one."  I don't know the CFM/Static Pressure info on these (I think the labels were removed -- kind of like filing the serial number off a handgun, lol) but I think if you go to Dogie's review of the ASICMiner Tubes, he has some info on the fan THEY use -- and I bet it's similar.