Original unit got wet and couldn't be saved. So, I picked up a replacement from a '00 E38 and installed it, but the sound is muddled and not clear. As I understand it, the amp needs to be re-coded.
Is there a preferred program for doing this? Any help would be appreciated. Thanks!

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E38 740i (9/94, GF61, JPN: M60B40, ZF 5HP30, 3.15:1)
E53 X5 4.4i (5/06, FB53, US: N62B44, ZF GA6HP26Z, 3.46:1)