Hi Peeps,
first post.
I just switched the stereo in my "new" K11. The old and the new stereos both happily earth through the aerial plug (the stereo doesn't work without the aerial plugged in). But if you have an earth cable then you do want to screw it down to the car body somewhere. If you leave it flopping around it might touch something it shouldn't and create a short circuit... blown fuses, melted wires etc might follow.
On my Micra, once I got the centre fascia off (two screws under the ashtray then unclip) the stereo was held in with 4 screws. Only the right 2 are suitable for screwing an earth to as the others only connect to plastic.
