Hmmm, new guy here ... I just purchased a late 2004 model coupe that came off lease but I haven't picked it up yet. I'll know more about the stock stereo in about a week after I have time to check it out personaly I can only remember 1 Crossfire and it was a simple job. If I remember we used a VW harness and it worked just fine with the factory amp. http://www.installer.com/cars/by_car.php?car=CHRYSLER Search your year model at Installer.com and see what they have to say, they are generally pretty accurate. Another thing is Pioneer headunits are switchable to send rear speakers full range or just Bass. If you select rear to be Bass only you can run the rear outputs of the radio directly to the rear spkrs and have total control over Freq & output level independant of the front spkrs. Just a thought. I hope I like the Crossfire as much as I think I will. I love MB enginnering. The ML320 I bought new in '99 is still going strong, looks like new and has been troublefree!