Are you going to run a thermostat?
What I found when I tested a dozen thermostats, is they have different "delay" settings even if they are the same temp. I put them in boiling water and watched them with a stopwatch. Some took 40 seconds, some took as little as 8 seconds. Obviously if a thermostat takes 40 seconds to open, you could overheat before it opened with a racing application. In '08 overheating was an issue for us, but after finding "faster" thermostats (mine uses two), in 09 it wasn't overheating that sent us home, even though we turned up the power a bunch, water got to 180 deg and sat there.