2 - The fan noise is really high, probe disconnecting one and it turns out that actually make noise are the cooling radiator, the other 3 are silent, no way to lower the speed of the two fans or your I change default by less noisy? (my BJ's in my living room, it's really annoying)....
There is not much of an option, to evacuate the heat, you'll need some kind of air flow. Put the machines somewhere else....
3 - 24h in btcguild, my gain was 0.05 BTC, is right? is little? Recommend me some other pool? (According to a calculator difficulty should win daily 0.07)
Over the last 24h I got 0.063/BBJet on BTCGuild which is about what I'd expect with variance (luck) and such