I don't know which Gov agency controls the rules of radio suppression, [ Maybe FCC or another enviroment control sorts],
but I can remember when Mopeds were first imported into the
States, they could not be Registered/ Inspected until a radio supressor/resistor was added to the plug wire end as it was not
a stock item.
So , I think there is some control on this . It may even be considered under emissions rules ???
I notice the 104 eng uses 2K.

I will do some homework on it.....