You can hook an empeg up to another head unit - Steve, one of the empeg directors, finally got his empeg fitted to his Volvo estate last week - he has a Sony CD head unit (I can't remember which one, but it's a basic single CD+RDS tuner) which provides his amplification. The empeg is hooked up via a Sony CD changer bus adaptor - this plugs into the head unit and allows a twin-RCA aux signal to be fed into the head unit.

I *think* kenwood do similar bus adaptors for their systems too: Alpine definitely do.

Hugo
(Who has stolen Steve's sony-stalk controller and almost has it wired to the empeg's serial port...)