I am trying to replace the stock unit in my 318ti. I bought a harness and hooked up my new pioneer but no sound. I spoke with circuit city and they told me i would have to rewire the entire car if i had a amplifier because they did not have a harness for that. What do I need to do to get this new stereo in? I also did not have the code when I went to put the old stereo back in. I took it to the BMW dealership and the computer could not find the code. Any suggestions on getting around this need for a code or what should I do?