I have 4 ZM-F2's bought from SVC. Currently, one is on Alpha8045, another is used as Antec1040B's exhaust, both at high speed. My comparisons (only let them blow at me closely, no tools were used) of:
92mm ZM-F2 normal(53cfm/36.1dBA). noiseless(38cfm/20dBA),
80mm Panaflow L1A (24cfm/21dBa)...