Not that my thoughts are worth much but...
I think Harley will sell the bikes from the factory with Stage I,II, III, and IV already installed. That way they are insuring that the bikes are EPA compliant when they leave the plant. It will allow them to be able to enforce the warranty much stricter. And performance enhancements beyond those 4 upgrades would render the engines out of compliance of EPA standards and allow the MOCO to disavow the warranty.
My hometown Harley dealer I buy from had to sent theiir techs to a 2+ day class taught by Corporate HD on how to find ways to void or cancel warranties. HD is posturing themselves to eliminate alot of money they shell out on questionable waranty claims. And they can use the EPA settlement as a tool to define the grounds for warranty denial.
I am not condoning it, but that is the direction I see this going and will save the MoCo money because they can void your warranty if you have done anything to your bike beyond cosmetics. They can say that your modifications caused a component failure even though we know it to a design flaw.
Some parts of what I have shared or maybe all of it, or probably none of it, might be the case.
Used twin cam bike values might be going up. It would certainly drive the values of any used bike up that have no remaining factory warranty left. Then the extended warranty covers you and your torque/hp desires to go wild.
Just thinking about this makes me miss my 2015.....