If you are using just the plug & play unit (IE the Roady XT) I would suggest you stick with the lighter plug, OR route the wire, and use one of the "spare" slots in your fuse block. Cutting into the stereo wiring for an external unit may be a little hard on your stereo fuse. Remember, it does take more power to run the display and lighting for the external unit than it would for just a controller/tuner for a sat-ready stereo.