Do I have to splice the cars wires in order to hook them up to the two units?

You seem to be mostly concerned with the power wiring to run the two decks. Have you given any thought to the outputs from the decks?

Are you going to run the output from the Panasonic into the auxilliary inputs of the empeg? Or vice versa? The first way, you will need an external amplifier, the second way you will use the amplifier built into the Panasonic -- but this only works if your Panasonic has auxilliary inputs; most consumer level CD decks do not.

If you are going to run the decks independently, then you will need the external amplifier plus a signal switch -- the Sony XA-39II is the only one I know of, and Crutchfield the only place I have found them for sale. And you will have to make sure your Panasonic deck has line-level outputs, not just speaker level outputs.

Wiring the power to the decks is the easy part. It's dealing with the outputs where things get tricky.

tanstaafl.