2002 Ford Escape XM radio

I am installing a Delphi Roady 2 XM radio on a 2002 Ford Escape for a friend of mine. She wanted to hardwire it instead of using the supplied cigarette lighter adapter. My problem starts there. I have all my wires ran from the battery to the unit, fuse included, but it has a 6V input instead of 12V. Is there a way that I can install a resistor inline or something else I can use to step the voltage down? BTW the original voltage converter was in the actual cigarette lighter plug. 

The best thing to do is to use the adapter, and buy a seperate cigarette lighter outlet to hardwire in and tuck away somewhere.My ex once told me I have a perfect face for radio.

I'd tell her that's how it's going to be, maybe that's why I'm still single, though.  On a serious note you'd need a power resistor, since that unit has a 3A fuse, I believe.  You could wire a 6 volt zener diode in parallel with the unit, along with a bleeder resistor in series and that would give you a steady 6 volts.  That way the value of the resistor really doesn't matter all that much, so long as it can take the current demands of the XM piece.  Otherwise, you'd have to experiment with different value resistors (starting high and working down) until you found something that would work.My ex once told me I have a perfect face for radio.