stock 2002 BMW 330 with no DSP and no CD changer. I have a delphi skyfi2. I want to install it directly to my headunit using the auxiliary output, however my car doesnt have one. From what i understand, i need to buy this.. http://www.logjamelectronics.com/soundauxbmw.html ..and this will hook into my trunk (cd changer wiring) and i will simply run a Y cable from these two RCA inputs straight to the back of the XM? Is that all?