One problem related to engine noise has been reported for the 2015 BMW 328. The most recently reported issues are listed below.
While attempting to pass at approx 50 mph on a two lane mountain highway, the car suddenly lost power, warning lights and buzzer sounded. The message on screen reported 'drivetrain malfunction, drive moderately'. The car continued to operate, vibrating badly whenever I gave it gas. We limped home, shut it off. Two hours later I restarted it and all the error warnings disappeared and the car is running normally again.