The thing is CA has noise laws already on the books and have had them since I can remember(I am 68). When I was in HS in the 50s we had to watch out for cops if we had loud pipes on either our cars or our motocycles, because they would ticket you if they thought they were to loud. This new law is just another way to get more tax money out of the people of CA and serves no useful purpose as it is a redundant law. It is not the people's fault if the cops refuse to enforce the laws already on the books.
Back in the 60s my cousin had a handle by the gearshift in his Chevy. Pull it back and the pipes got LOUD. On motorcycles we got turnable washer-like things at the tips called “Snuff-or-Nots.”