Funny you mention that, because I did some searching in the audio forums, and I went and looked behind the dash and found a pair of red & white RCA jacks. I'm assuming they're from my head unit. I'm gonna give it a shot. Where did you buy that jack?
Old car: '98 SVT T-Red
K&N air filter; Ford Focus RS shift knob. Off to be auctioned off somewhere.
New car: 2003 Honda Accord DX Sedan, 5-speed.