It's a numbers game, and you're overlooking the other side of it. The automakers have to engineer to a very low probability of failure because they deal in lar

It's a numbers game, and you're overlooking the other side of it. The automakers have to engineer to a very low probability of failure because they deal in large numbers. It's true a person in their garage can't match that engineering - but they don't have to. They only have to get to "reasonably" safe not "absolutely" safe. It's just like people putting turbochargers on their 90s Hondas. Naysayers could claim it's a fool's errand because if Honda, with all their engineering resources, didn't feel they could add turbocharging to their engines in the 90s and have it be cost effective and reliable enough, surely someone in their garage can't do it? But what they overlook is that if 5% of one of Honda's mass market cars blew an engine that would be a disaster, whereas a 5% chance an individual blows his own engine, which he may be able to replace for $500 to $1500: that may be a risk an individual is willing to take that a carmaker cannot.