So, drive the old car (I didn't trade it in, too much stereo junk to worry about ripping out just yet) and have tons of music to listen to on the way (with a better sound sytem) or drive the good new car that has only a 6 disk changer (ungh)

Any AUX input on the new cars stereo? Or if it has a tape deck (probably unlikely today) can it accept a tape adapter? Any other way to feed it an external signal?
Anyone you know that has an FM-modulator lying about?
The empeg can be temporarily powered by a cigarette lighter plug wired to a barrel connector (it'll think it's at home, but that's no biggy...)

/Michael