I did a loud shift fart on saturday when I flew past a couple buddies. Forgot to ask them if it sounded terrible/obnoxious from the outside of the car. Before that we were hanging out in a pub. When I was pulling up I saw they were seated in the outdoor area, so I drove past and made it gurgle a little bit. When I finally got to the bar they were like, we heard you, then we saw you, everybody here looked. I was like uh oh, was it obnoxious? They said naah it's tasteful.
One of these days I need to get someone to drive my car and go up and down the street while I just stand there and watch/listen to it. It's hard for me to gauge how loud it is from the driver seat.