This is what I used to hook up XM to the factory head unit (no DSP) in my wife's X:

http://www.crutchfield.com/S-Xvg7Gzy...asp?I=581DFBMW

Easy install - hardest part was running the RCA cables to the front under the carpet. You do lose use of your CD changer, but she never really used it anyway.

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2001 X5 3.0i (PP/WP/AP) Traded at 213K miles
RARE White on Black - Why does everyone get Tan??
First E53 with 215s on XOutpost!!