I did this in my E38, and another simple thing you can do is go in eBay etc. and buy the updated microphone. It just snaps in, very simple. I did it because many friends reported the person on the other end of the line said it was a noticeable difference from the mic installed a decade ago. I think one mic is Green and one is Black, if I can find the PN# I will edit the post.

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740iLDUKE
01' DINAN 7 S62 Swap - Stratus Grau
(1587 produced in SG 440)
02' 4.6is DINAN X5 S2 Supercharged
833/3258 produced | 1/27 Dinan X5's