As far as I can think through, it doesn’t affect other electrical systems any more than popping an aftermarket head unit in its place.

The only caution to take is that the stock head unit has a plastic finger(?) that pokes into a hole in the back of that cove. This sensor hole is tied into the (dealer installed) BMW Alarm. Any thief time-traveling from the ‘90s looking to grab a head unit for his MySpace listing will trip the Z3’s alarm when popping the unit out. The solution others mentioned was to unscrew the plastic finger from the head unit and affix it into the hole. — All this presuming you’ve got (or plan to get) the Alarm module for the shelf forward of the glovebox.

 

My ride already has an aftermarket radio installed. I have removed it several times to work on the console . so.....?? I never had any scary moments so far. Maybe this car never had the alarm?