It’s unlawful to have someone say what you can and cannot do to your vehicle many stock exhaust  stop power and cut torque that your vehicle makes and with a after market exhaust you can gain power.As long as your vehicle still passed emissions and is still good to the environment there is no reason you should have to take your exhaust  off.If noise is a concern make areas where modified exhaust are not allowed and places such as rural issues you can have a loud vehicle as long as it still passes emissions and is good for the environment.