the amp is what needs to be coded...the e38/e39/e53 all use the same amp, but it is coded based on the equipped options & parameters of each vehicle. A used amp from an e39 put into an e38 or e53 will work, but the sound will be muddled because it is set-up for the interior dynamics of the 5 series...not the 7 or X5.

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Q {BMW CCA Member #191509}
2006 E53 X5 4.4i (Sterling Gray) 12/05 mfg date <<~>> 97 740iL (Arctic Silver) 3/97 mfg date
(SOLD)
99 540iT (Orient Blue) <<~>> 95 525IT (Alpine White)
91 735iL (Schwarz Black) <<~>> 85 325e (Bronzit)