I'm not convinced, however, that this insane tax is valid only for Italian aircraft though. If so, it would be only too easy to change to another register such as Malta or the IOM for private aircraft. (Not as if any wealthy Italians would want to evade tax though
)
That's the reason that comma14bis was introduced, to avoid Italians registering their aircraft outside Italy.
But as I said most if not all Jets, turboprops and helicopters are under AOC, so they will not be touched by this tax.
Regarding foreign aircraft, there seems to be a bit of confusion, as Dirk85 said, comma14bis(relating to foreign aircraft in Italy for 48h) was briefly introduced but quickly removed from the final legislation.
I'm anyway following the issue and waiting for the final drafting.