I found that the similar topic was posted in MY, but wanted to gather more information if it is true in M3.
To add more, from a forum in South Korea, people claim that they are experiencing the difference between old and new models, saying that now the sound is more likely gathered at front side. They pointed that the audio of previous model (before 2022) distributed to entire cabin more likely surrounding audio before 2022 model.
Audio system changed to 13 speakers?
But previously it said "14 speakers, 1 subwoofer..." now it says "13 speakers, 1 subwoofer..." I don't know the previous layout of the cabin speakers, but I'd assume if there were 2 close together somewhere in the centerline of the car, they might have replaced that with a single speaker...
teslamotorsclub.com
To add more, from a forum in South Korea, people claim that they are experiencing the difference between old and new models, saying that now the sound is more likely gathered at front side. They pointed that the audio of previous model (before 2022) distributed to entire cabin more likely surrounding audio before 2022 model.