No...not specifically for Maserati (you've probably realised by now anything to do with Maserati is rarely uncomplicated)
However...most cars have similar requirements & a ground wire or two is the norm. If you search ground wire for Ghibli you'll come up with one...only.
Here is a result I found on the net that relates to ground wires...'generally' in automotive use.
Of course Maserati is a 'magic' car...but even so some basics have to be followed...even grounding wires
Good luck...Mark (hope this helps a little)