interesting "An exhaust system shall not be deemed to prevent excessive or unusual noise if it permits the escape of noise in excess of that permitted by the standard factory equipment exhaust system of private passenger motor vehicles or trucks of standard make."
This could be argued as any 'factory system of any car.' I am not a lawyer and it is flimsy at best, but a stock Cobra is pretty loud. so your exhaust could have to be in excess of any factory exhaust of private passenger motor vehicles or trucks.
Interesting. would like a lawyer to comment but the law does not specify the OEM exhaust of your car... I know BD mentioned it but I wanted to Highlight it.