I can see that this reply is a little late, but to anyone else, using a QUALITY line output converter behind the radio will yield best results in the crossfire, using the rear outputs. This will give you the best signal to connect aftermarket equipment. I have done a complete sound system in my base model including MB Quart components up front, an Audison LRX4300 (mounted behind the drivers seat) for the speakers bi-amping them, (2) MB Quart 10" Subs with a JL 500/1 (mounted behind the passenger seat), Alumapro 5 farad cap) mounted under the carpet under the passenger seat), an Alpine CDA9835 headunit with ipod adapter in console. I ran new wires for everything so if you have any question about installing anything in the crossfire, PM me.