The supreme court left it kind of vague in their ruling. The courts are supposed to decide, but for something like this no matter what the lower courts decide, any ruling would almost certainly get appealed up all the way up to the supreme court. So what is or isn’t an official act is basically boils to whatever the supreme court decides it to be.
Around here, people pay a lot of money to make their cars/trucks/bikes sound loud and shitty. Yeah, you do occasionally see a clapped out beater being loud too, but they are the rare exception now.