Hi, guys. Im getting a mustang gt as my second car soon and i want to do an experiment of trying to find the loudest exhaust setup while at the same time passing the emission test. Where I live, they only check to see if you have the engine light on so i will be very appreciate if you guys could give me your opinion as i dont know much about cars and the different exhaust system. Ive seen people say there are setups louder than a straight pipe and that left me confused because I thought...

Loudest setup with a cat on?