Well I am assuming the GM 9-pin version will work for my car, a '98 pontiac grand prix. It gets delivered tomorrow, not sure when I'll have a chance to try the install (in the middle of home remodeling).
As far as worrying about power supply it's not a concern with me, the radio stays on for 15 minutes (or until a door is opened) after the car is shut off. I don't know if that's what was meant by Ferret's post. I never leave my Karma in the car anyway.