an alarm that if anyone tries to get into those areas without the remote then an alarm will sound???
the Trunk Monkey. or a pit bull
a perimeter alarm even a loud noise will set it off
Virtually all car alarms will allow connections to cover those areas, except the gas cap. Your best protection there would be a locking gas cap. If you want an alarm recommendation I'd suggest a Viper 350XV. Be sure to tell the installer you want trunk and hood coverage.