The quality of the sound system in the E39 is driving me mad, mainly because as the car has such a quiet cabin it is a pretty good place for listening to music. The BMW business stereo CD is just not meeting my requirements. It sounds awful, very hollow with no bass and it hates any sort of volume.
I was wondering if anyone has upgraded sound system and if so- how? And more importantly with what results?

Here is few pic. one of my experiment

I kick out stereo
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time for some sound deadening material
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door cards upgrade
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first look
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A-pillar tweeter pods
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car is still under construction