I know mine has 10 speakers and its not to bad not as good as my last car lexus is250 mark levinson system but the funny thing i turn down the stereo in favor of listening to the beautiful exhaust note coming from the 335.
LEXUS stereo up load
BMW stereo turned down listening to the engine sound.
bmw tuned their exhaust spot on.
I will take a look at it maybe they have a car that's installed this system.
THE BEAST MHD Flash Tune / AFE DCI Intake /M3 suspension/Forge Intercooler/Alpina B3 AT Flash/Bird's B3 Suspension/BMW OEM M3 Steering Wheel and DCT Paddles/LUX V4 Angel Eyes/CIC Retrofitted