a)
The car, Otto, has a world record for having been to more countries than any other car.
b)
The word order has been inverted, ie. auxiliary + subject + verb clause.
- If the car had been a modern car, it would never have completed the journey.
- If he hadn't mastered the mechanics himself, they might have experienced more breakdowns.
c)
- formal
- And one that Holtorf says would have been impossible to achieve had he tried with a modern car.
d)
- Never before has a car travelled so many miles.
- Not once did the car break down so badly that he couldn't fix it.