Depending one where you live, it can be.
The other problem is that the Road and Traffic Authority (RTA) is rather strict on the condition of your car if you want it to pass registration. Rust is one of the things that they take in to consideration.
You might not have HEARD of them, but you have seen their inspiration... The "new" Pontiac GTO is modeled after the Holden Manaro. (See foreground car in below pic)
As far as a 3 door... typically, hatchback's consider the hatch to be a door... some are "5 door" if it's a wagon. Other's still like the Saturn SC1 & SC2, and various pickups have the little half door thingy behind the driver's side doors that opens the opposite way to give better access to the 2nd row of seats.