Really? How have you defined common? Where is that data from? I can't imagine anything more than a tiny fraction of car owners are doing this. Most people are not hacking their cars, building Raspberry Pi controllers for their toilets, or have any desire whatsoever to side load an app on their iPhone. The HN community is not representative of the overall population.
It's common enough that there's a legitimate industry around that and a lot of auto-tuning shops will do it on request. In most cases though it's just editing the built-in data tables rather than completely replacing the firmware, and it's often done for engine performance reasons rather than bypassing safety features.
Mechanics do it often, as do people who work on their cars. It isn't the Hacker News segment that is doing it, but the people who work on cars for a living or for fun.
Really? How have you defined common? Where is that data from? I can't imagine anything more than a tiny fraction of car owners are doing this. Most people are not hacking their cars, building Raspberry Pi controllers for their toilets, or have any desire whatsoever to side load an app on their iPhone. The HN community is not representative of the overall population.