Sounds like you have the factory cats. If it were me, I'd find a stock catback nearby (maybe check through your local Mustang club), swap it in, get the inspection, and then swap your Borla catback back on. As suggested above. It's the cleanest/safest method to get the inspection done without any hassle with the state.
Which Borla catback do you have? If it's a Stinger, the loudness factor likely got you nailed at the beginning of the inspection.
Which Borla catback do you have? If it's a Stinger, the loudness factor likely got you nailed at the beginning of the inspection.