To what I can find the RB20 is what I need I think. I do not have any RCA inputs on my deck. It has a IP-BUS which my XM goes through. The only way the XM will work actually. To what I can tell if I get this device, it will pass the XM through when I have my deck in XM mode, or pass the RCA through when I am in AUX in mode. I guess I need to spend another $60 bucks. eek. Anyone else have this setup?