I have a new 09' 335. I just noticed today that exhaust is coming from only one of the exhaust pipes. It appears there may be a small amout coming from the driver side pipe, but noticeable from coming from the passenger side (when you put your hand in front of it, you can feel it. nothing coming from the other side). Should I be worried? I'm guessing, yes, i should make a service appointment.
Look in the pipe. There is probably a vacuum operated flap designed to muffle the sound more at low revs/loads.
its normal for only 1 side to work. there is a vacuum valve in there that many do the famous golf tee mod to open that side for a better sound.
I also recall reading that only one side is open at cold start. They both open when engine warms up. I agree your situation is probably normal.
