N Registered aircraft make sure if you ever travel or transit through Italy to have proof of VAT paid.
Last year there was a frenzy going on which resulted on " Guardia di Finanza" impounding all N registered aircraft they could get their hands on.
Any aircraft was and will be grounded without mercy if they catch you, you'll have to prove payment of VAT by producing custom clearance formular from the EEC country in which formalities were done.
There has been an issue apparently solved now with imports through Denmark as well as T7 ( San Marino) Registrations -a small independent state like Andorra- that offered an escape to italian owners not so much for tax related issues but to circumvent the insane inextricable ENAC (Italian CAA) practices a nightmare for any owner to deal with.
In addition, a decree was also issued last year by which any aircraft entering Italy regardless of registrations and vat issues should pay a Tax based on weight typically for a small single around 1'500 euros. Said tax was due after 48H on territory, now extended to 6 months.