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The Masiv radiator rubbed on both sides of the AC condenser. This was not as bad as it seemed as we were able to fix it by using spacers to move the condenser forward. Not knowing that it was going to do this made us waste a lot of time fiddling around. If there were instructions and spacers provided it would have not been such an issue.
The real show stopper was that the Masiv radiator put the fan assembly hard into the HKS supercharger. We had to keep everything unbolted and floating to allow the radiator to move away from the supercharger during the test. There is no way that this would be acceptable for any kind of actual driving. The Masiv radiator might interfere with forward mounted turbo kits like Crawfords or Greddy and forward facing headers that are a tight fit to the front of the engine and radiator like Nameless or Cosworth. It would fit OK with a top mounted supercharger like the model from Innovate Motorsports.
Due to its size the installation of the Masiv radiator was a lot more involved with the core support having to be removed as well as the AC condenser. 
For results, both radiators, the CSF on the left and the Masiv on the right were able to control the engine's temperature on the dyno without thermal runaway like we feared. In fact once both radiators reached equilibrium, they held the coolant temperature steady and would drop the temperature really quickly even with limited airflow. You can see how the coolant temp is pretty steady for both radiators even though the air temp in our dyno room is climbing due to the heat created from so many back to back runs. Looking at the data, both radiators work well but you can see that the CSF radiator is the winner with faster recovery times and lower peak temps even though the ambient air temperature is actually higher during the CSF test than the Masiv. 
The temperature in the Masiv radiator fluctuates slowly, we think this is because of the radiator's heat sink thermal mass plus the additional coolant it holds creating even more thermal mass. The mass plus the lower thermal conductivity of the rows of brass fins and thicker core cause greater swings of temperature. The peaks are higher but the valleys are somewhat lower. The Masiv did control the heat generated by the supercharged engine but cooled a little worse than the CSF. This is probably because the three rows of fins are less effective than the wide tubes of the CSF and the Masiv borders on being too wide for best efficiency as a heat exchanger.
The CSF radiator has a lower peak temperature as the coolant exits the engine but a higher post radiator temp. However the average temperature variance is less and the temperatures are more steady. The CSF also drops the coolant temperature faster after a pull, with the temperature way down before the next pull could start. You can see the coolant temp exiting the engine drop faster compared to the Masiv by the steeper slope of the line. The CSF cools at a rate of ~0.8 degrees F per second whereas the Masiv is ~0.7 deg F per second. This is true even though the ambient air temp during the CSF test was higher. Some of you are probably wondering why the temp of the coolant leaving the Masiv is colder than the CSF, yet the CSF keeps the engine cooler as shown by the temp of the coolant leaving the engine being lower. We think it is because the Masiv has a lower mass flow rate of coolant compared to the CSF. So basically, the coolant flows slower though the Masiv giving it more time to cool off. But this also means the coolant flows slower through the engine.Although both radiators cool pretty well and both were capable of keeping our supercharged FR-S cool under tough conditions, we feel that the CSF is the clear winner in this competition. It cools slightly better, keeps the engine temp more constant, it fits better, dropping in with no fuss with a wide range of supercharger, turbocharger and header combinations and is less than half the weight of the Masiv. Although the Masiv radiator is good, the CSF is the radiator we would pick for our own cars.
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