Sad to see this thread has died, I think it could have been a good sticky. A buddy of mine was messing around with his reader (I don't know if it was dBA or C) and we got up to 103dB in my cabin with the windows up.
I removed the cats and put on Beluga resonated test pipes, and I've also had a muffler delete... I'm planning to go to an exhaust shop soon to get the car quiet downed a bit as people in the area aren't too happy about my car at 2am.
I'll see if they have a reader by any chance and update...