This happens not-too-infrequently in the car modding/tuning world --- the former, that is; to my knowledge no one has blamed the original manufacturer, much less successfully sued, after him/herself modding the ECU of a car and blowing up the engine.

Don't forget that a lot of other safety-critical components of cars (e.g. brakes, tires, etc.) have aftermarket replacements --- many of which actually perform better than stock.

If this "safety" attitude was prevalent since the beginning, we'd have cars that can only use approved fuel, no aftermarket parts would exist at all (their manufacturers being sued out of existence), and it'd be illegal to drive them on roads not approved by the manufacturer.

I will resist the urge to post that famous Benjamin Franklin quote this time.