I have been using watercooling for years now. I have a standard Eheim pump linked to a heat exchanger on the CPU and, from there, to a passive radiator. The liquid transits via supple plastic pipes.
One day, a bad case manipulation on my part led to one of the pipes being almost bent in two - severe kinking ensued.
The PC was running at the time, and I didn't notice the problem until the next day. When I did notice that the pipe was letting very little water through, I checked the hardware monitor in astonishment - the temp was three degrees above the usual 41°.
So you don't need the Niagara falls to efficiently cool down a chip. Your local stream in the backyard will do fine. A little hotter than it could otherwise, but fine still.

I have built a few water cooled systems in my day so I have agree with the original author on this one. Yes sure you can restrict the flow of coolant but its not really reccommened. I have talked to the guys at swifttech and they test out all kinds of configurations to get max cooling with real scientifc based tests. I am sure based on their newest designs they have improved considerably since the days of plastic crimps for connections to the radiator.