They might have to be that way to buy them new from the factory.
But the moment it belongs to you and even before you leave the lot, you can have illegal aftermarket exhaust systems installed that not one governing body in the United States, nor most of the rest of the world, will come close to enforcing any noise or emissions laws against.
But the moment it belongs to you and even before you leave the lot, you can have illegal aftermarket exhaust systems installed that not one governing body in the United States, nor most of the rest of the world, will come close to enforcing any noise or emissions laws against.