I get a faint whine in the M3 but only on the tuner (haven't tried auxiliary). Via the MP3 player there is no whine at all.

The antenna in the BMW is a powered antenna though so I assume it's something to do with that.

Because it's fairly faint I've not bothered to investigate it much further.
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Christian
#40104192 120Gb (no longer in my E36 M3, won't fit the E46 M3)