I put a Kenwood in my 02, non-DSP, no nav E53. Crutchfield walked the dog for me…what fit, harnesses, including the one that allows for steering wheel controls, and decent instructions. You are probably more astute with electronics stuff than I am, but it was the easy-button for me.

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Current
Original owner 2002 E53 X5 4.4i to 4.6i swap
2025 G06 X5 50e
Former
1972 Audi Fox
1986 Saab 900S
1996 BMW Z3
1998 BMW E36 M3 Sedan
2004 BMW E46 M3
2006 Audi A3 Quatro
1993 Mopar 318 Jeep Grand Cherokee
2015 V6 Jeep Grand Cherokee