instead of FM modulator, have you thought of getting an auxuillary input device that will plug into your factory radio and let you play your satellite radio through the factory radio? they`re probably more expensive than a FM modulator, but they are suppose to sound better since they plug directly into your factory radio.
i tried looking for something similar to hook my iPod to my factory Mach460 and came across a forum board for xm radio, although i don`t have the bookmark right now. well, let me know if you want it, i can get it later when i go home from work.
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