My son has an 01 E53 with DSP. I had to take his car drive his car the other day, and I think the audio is better than my 12 E70.

Is it possible to add an E53 subwoofer to an E70? Seems like I can find a unit in decent shape on eBay for ~$100 US.

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2001 E53 3.0i
2012 E70 xDrive35i