Are the vehicles owned, rented or borrowed? see above.
Does the leader drive, or does he/she have a chauffeur? He has a chauffeur, who is also his wives' and children's bodyguard.
What special modifications do the vehicles have? all the vehicles have weapons, Gundarium armour plating, scanners and other fantastic features you'll typically see in a scifi movie.
Where are the vehicles kept when they are not in use? in the vehicle depot in the Pearl Palace
Who provides maintenance and repairs? Japanese and Korean engineers
Does the leader need a driving licence, and is he/she required to follow the rules of the road? no, because he's the frickin' Heavenly Emperor
Has the leader ever been "pulled over" (stopped by police) while driving? lmao like anyone would be brave or dumb enough to do that
Opinion question: What do you think of our Phoenix Empress' taste in cars (Audi A4, Porsche 911)? try Lamborghini