The dollar part is pure personal preference. You would need two pairs of speakers, a sub, and a four-channel amp. That can be anywhere from $350 for basic components. I would probably spend $1,700 to $2,000 if I were buying audio components for my car. Installation would be on top of this.

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2000 E38 750iL Highline Edition, Upgraded with the lastest 2006 X5 Electronics
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