If it's illegal for MMC, it's illegal for the owner to do the same.
If we as the owner removes a catalytic converter on our car and it fails the sniffer, we can be fined just like a manufacturer.
It's just that most of the time the "man" will not mess with an individual, but take on a company to make a point.
Personally, I would not hesitate to back convert to an older regulation, especially in this regard.
