I'd have a few select names that would be in violation of WikiAnswers' terms of use if I posted them, but the general term is "joyrider".
jailbreak
Joyrider
You can call it a vehiclist
Impound lot.
USA is the country drives the most cars
basls
Motorist.
NOT unless it was stolen. Stolen cars are reported stolen. Cars securing a loan in DEFAULT are reported as DELINQUENT to the credit bureau. If you choose to report the car stolen, go ahead. I would not reccommend it though. Filing a false police report is illegal in most jurisdictions.
A car collector?
RICH
A car mechanic.
Mechanic