In addition to the 911, i also have an Austin Healey 3000 fitted with a single muffler side exit 'works rally' exhaust rather than a twin box rear exit factory system. It regularly sets off car alarms in the street and on a recent decibel limited track day, made the man with the noisemeter fall over clutching his ears when i revved it to the 3/4 of the rev limit
Whilst i had a giggle at the expense of his hearing, it meant i couldnt take part in the track day
(The track is Goodwood where they have loud and quiet track days due to the proximity to housing)
Andrew