"I don't know how hot the power stages run, but computers run anywhere from 100-160F with averages around 110-130F. "

Well, that is a variable that is almost impossible to answer. The power stage is behind the battery on the 240 (LH drive) so it completely out of the airflow. Ambient temp of the engine bay before the engine is running can range up to about 125-130F when the outside temp is 105F. Our radiators range up to 220-230F so lets just say ambient temps up to 160F running.

The variable is that I suspect the power stage itself maybe run cooler than (engine running, under hood) ambient due to the heat sink's connection fender. Ever felt piece of body work that was over 130F? I have but it was working in Iraq when daytime temps averaged 118F for 6 months out of the year.

In the end, I think the elements play as much a role as the temperatures involve. Outside of marine and aviation applications, pretty much nothing sees the application to salt spray, extremes in temperature, etc, etc. Now we understand why Volvo fought so hard to keep so many of the vital electrics inside the cab when others where hanging them all over the engine bay. In the end, Volvo was probably wrong about that but the thought process was sound.