> "Which competitors to $car_manufacturer engines are there for $car_manufacturer cars?" Interesting and rather unfortunate that you should use that example, s

> "Which competitors to $car_manufacturer engines are there for $car_manufacturer cars?" Interesting and rather unfortunate that you should use that example, since the landmark Magnuson-Moss Warranty Act famously invalidated automakers attempts to revoke their products' warranty if aftermarket parts were installed. It's a clear example of a consumer-hostile practice that was deemed to be unfair and regulated, even though no monopoly was involved.