No they're paying for the emissions controls. The people that buy the tractor I have, usually illegally turn the screw and get the horsepower back. Nothing is stopping them from doing it, it is all over youtube, can be done in a few minutes.

If it was actually about "price discrimination" they would do something to stop you from tuning them back to the full horsepower other than "please definitely don't do this thing we made it super easy for you to do, hint at in your repair manual, and is plastered all over youtube probably indirectly by advice of our own mechanics."

To use your BMW analogy, it would be "we put a screw to turn on the heated seats, but please don't do that". That would not indicate someone actually seeking price discriminations, but rather providing people a way to save money getting around an expensive rule, but also they will charge you $4000 if you really want to comply with the law and add a big "save the environment" doohickey on to the seat heater.

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You cutoff my quote to change the context of what I was saying. Preponderance of the evidence is pretty clear what you're saying doesn't apply here, even if it applies to something else.