The manufacturers can certify their changes to be emissions legal. They already need to go through the process to certify every new model of car they make and have the equipment and know-how to do the paperwork, so it's not a huge deal for them.

You can go through the same process, but you likely can't afford it.

Makes sense. In that case I will accept a one time fee for a dial on the dashboard that says

- economy

- normal

- performance

I believe that Toyota and a few others already did something like this in the past. I will not be subscribing to a service with a vehicle provider unless they are giving me an incredible incentive to do so but I can not imagine anything that would be both an incentive to me and to the vehicle manufacture.

Good point, it opens up some sort of gvmnt regulated permissioning for upgrades bureaucracy for newer vehicles...while other bureaucracies crack down on individuals performing the same actions.