I have one of the Delphi SkyFi XM radio receivers installed in my car and I absolutely love it with the exception of having to plug it into my cigarette lighter to power it. Every little bump interrupts the current and causes the unit to turn off, and I can't use the power port for other electronics (i.e. cell phone charger)

. I'm thinking about hard-wiring it into the car's electrical system, but the unit uses 6V and not 12V current, provided by the plug-in adapter. Any suggestions for how I might wire it directly into the car and get 6V? Thanks for any help!
Matt