Sadasius - I am using two 120 mm Scythe S-Flex's at 12 V and 49 CFM. The Thermochill 120.2 can handle 150 watts without problems.

Dejanh - I used the loop I did because this is an average representation of what to expect for both temps and flow in a real installed and running setup. The flow meter idea is fine, but as long as same loop is used, and no variable changes but block, .... it is apples to apples.

Vapor - Bernoulli's hydrostatic equations for closed connected loops. I am not in an argumentative mood, just I have to disagree with all the pumps turned off and the side loop. The best testing setup you can acquire with the tools listed in your methodology section is similar to the setup this guy used at the systemsextreme website back in 2001 -2004 (cant remember name now but will get it for you). The XT, GTZ and HF are all machined fine and without problems (I checked their bases but pictures can be provided if needed). P4 is getting higher flow rates cause it has 7 channels cut in it. P1 is getting less flowrate cause it has 2 channels cut it.