Except we're not talking reselling, we're talking about modifying. It's perfectly legal to modify the book you bought.
Which is why the government in the USA specifically changed the law to exempt vehicles from the DMCA after that was used to prevent modifications. Do you have any examples using a law other than the DMCA? And don't go with any licence agreement law either, because as has been pointed out repeatedly, nobody here signed an agreement.
I'm going to guess you have zero personal experience with writing custom flashes for cars or editing existing files.
Can't argue with someone who doesn't know the topic.
Fk the DMCA. This is simply theft. You can go all Open Source For All, No IP!!! crap if you like. Every Ponzi schemer can justify their actions down to the dollar, as can the inside traders, and bootleggers, tax evaders, etc, etc.
Go the fooler route. It's easier, cheaper, faster, and legal. If you don't know what a fooler is, you should not be modifying drivetrains.