One thing I would really want answered is if its better to use a 140mm fan, instead of a 120mm one.
Hopefully Mike will post an answer. I would like to hear his thoughts on this matter.
Here is my much less authoritative thoughts on that question. I share that question with you. I have come up with only two plausible reasons.
1. There is just less competition in the 140mm space and with fewer competitors it has just worked out the 120mm market has produced some better winners (more entrants in the race)
2. The other reason is maybe give the viscosity of air, the scale of the motors, etc... that 120mm is just a sweet spot. (yes this is weak... but I am grasping at straws)
Anyways, neither of those may be the answer Mike comes up with. But I have been thinking about it. It is the best I have been able to come up with.