I don't think that will work, and here's why. The earlier radio's don't have an AUX selection in the menu, I think the 2004 up radios do, it's a firmware issue. And if you buy a used 2004-up manufactured radio I believe it still won't work for some reason. Do a search for AUX cable and you will find a ton of data on this subject.

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2002 X5 4.6is
1999 C5 Corvette
1992 Mitsubishi 3000GT VR-4
1994 Kawasaki ZX-9R
2005 Mazda 6 Wagon (Wife's)
1991 Mitsubishi 3000GT VR-4