Ugh, is all I can say, it's impossible until you have obtained your Carta d'Identita. We tried everything, really, everything we could think that might possibly work, to no avail.
After arriving from California with our Elective Residence Visas in our passports, we rented a car. The lowest price was to pay in advance by the month. It cost about 1200 euros per month ;-(. So we tried to find a way to buy a car without papers. We made good friends with an Italian neighbor and he was shocked at the price we would be paying for five or six months before receiving a Carta d'Identita, so he offered to fill out the registration forms in his name until we could take possession of the car.
So we went with him to a dealer and he managed to talk them into selling us a used car. We wired the money and were so happy until our neighbor found out he could not take possession of the car because he would be liable for fraud if the carabinieri found out. Well our neighbor backed out of the deal.
For a few months the dealer kept the car, but eventually we gave up and asked for our money back. He gave it back but kept 20% because the paper we signed said if we backed out of the contract that was the penalty! A Catch-22 situation!
So we bided our time. The week we entered the country we had applied at a post office for the "Permesso di Soggiorno" and were given a date that was two months later to meet at the police station to officially apply for the"Permesso." Things went fairly smooth, except we had to go back for two more appointments. They never asked to see anything more than our passports, much to our surprise (we carried a stack of documents we had used during the eRV application in California). They fingerprinted us each time, which seems redundant, but . . . hey, who knows, the Italian bureaucracy is inscrutable. But four months after arriving, we were given our laminated "Permesso di Soggiorno" cards. With that (which means the Italian government said we can stay in the country for a year), we were able to go to Assisi to apply for Residenza in the Comune (like a County in the US).
Again to our surprise it was super easy, but the appointment made was a month after we got the "Permesso" card. Eventually we were given an official paper that said we were now official "Residents" of the Comune di Assisi. NOW we thought we can buy a car! So we took our papers to a new car dealership, thinking that a new car would have the advantage of the Dealer doing all the registration for us.
Having received a paper from Assisi saying we are residents, our next appointment, to apply for the Carta d’Identita, was given us as April 21.
Meanwhile we took our papers to an auto dealer in Perugia and saw a new Panda we wanted to buy, thinking our papers were now in order.
The dealer looked at all our cards: Codice Fiscale, Permesso di Soggiorno, passports, and the letter stating we were now officially registered Residents of Assisi, and he phoned one of his supervisors and was told that the paperwork would be sufficient to register a new car.
So we wired the money to pay for the car in full, and then the dealer took the car to be registered. But the Italian motor vehicle registry office would not accept them without a copy of the Carta d’Identita!!! We were shocked (as was the auto dealer).
Since our appointment to apply for the Carta d’Identita was not for yet another six weeks, and after that a few more weeks would be required to wait for the all-important actual Carta d'Identita card, we would have to continue renting a car for 1250 euro per months, for possibly two more months, while the new car we paid for languished in the dealer’s garage.
Luckily our consultant from "smartmoveitaly.com" was able to phone the Assisi administration office and chat them up with our sad story and they surprisingly acquiesced and moved up our appointment from six weeks in the future to next week! So next week, after officially applying for a laminated Carta d'Identita, we will only have to wait another week or two for the actual cards to arrive in the mail (or perhaps they will call us back into the office to pick them up).
Argh. The moral of the story is that YOU MUST HAVE YOUR OFFICIAL CARTA d'IDENTITA in hand in order to buy a car in Italy as an expat who is now a resident. period.
Having said that, another member of our grapevine said he "thinks" we could have travelled to France and bought a car, where it easier to register an automobile, and then driven it back into Italy. But who knows? Better to bite the bullet and be sure you have about six or seven thousand euros to spend on rental cars, or better yet, if you live in a small town, take buses and trains!