It would be a tautology if they defined it as the fastest car and excluded only the cars which were faster than it. No car produced in greater volumes is quick

It would be a tautology if they defined it as the fastest car and excluded only the cars which were faster than it. No car produced in greater volumes is quicker, and many which are produced in smaller volumes and/or for a lot more money are slower. That's a significant fact that's not diminished by shed-built customs.