Cathar why are you saying series is better? Parallel has much much less pressure drop because the flow is halved between the 2 rads. Also, those "tests" you mentioned are done with a constant 10C coolant/air temp difference, which means at more flow, MORE HEAT IS ADDED TO THE WATER TO ACHIEVE THE 10C air/coolant delta. There have been a few people who tried series vs. parallel, and parallel got better temps :P
Let me guess, now I'm going to be slaughtered for challenging the god?