I actually find it quite quiet, its just a deeper bassier sound. There is a slight drone at around 70 which I noticed on my first trip home but I haven't really been aware of it since then.
It does sound great though when you give the car the beans and accelerate hard.
I was worried it would be too loud but its perfect and tbh I wouldn't mind if it was a little louder. Definitely glad I didn't go for the resonated.
Hope that helps