Im putting a cd player in my sisters 05 grand prix (no monsoon/onstar/etc) and im a little confused on which harness I should use. I don't want to spend a lot of money on it and I don't care if she looses her door chimes. I was looking at the metra 70-2003 but I think I read somewhere I have to tap into another wire to retain rap, and to make the cd player to turn off/on with the car. What do you recommend? Thanks guys!