I changed my stock jet engine CPU fan with fan that I have been hearing people rave about.
Where? Not here I suppose: AFAIK Nexus PWM fans are not highly regarded here (on the contrary of their voltage controlled brothers).
However, you may give a try to the inexpensive Arctic Cooling F8 PWM, if you mind.
I would love to throw the Noctua fan in but I fear that it will not move quite enough air for a CPU. What are your thoughts?
I have a couple: it's a 1800rpm fan, so if in case it's fully suitable IF
your mobo's cpu fan header can effectively drive 3-pin fan along with PWM one. At anyway, providing that a fan is a good one, to have it quiet is a matter of control (SpeedFan, rheobus, et c.).