I'm not sure I have anything of value to add, but here's my ramble: I think a road-car and race-car express their value in different ways because they are valued for different reasons. A road car is valued for it's ability to perform, as it was designed, consistently over time; therefore, a lack of flaws, or a perfect car, is desirable because it implies that the item will work longer and better; also, the car can be enjoyed immediately and without waiting. Because mileage has a more immediate and clear effect on parts than time does, it gains priority in most peoples minds. If parts aren't given much opportunity to be rubbed, turned, scratched or soiled, then they must be better off. That heuristic is fed by the idea that there is a bigger market for a car that promises immediate, complete and durable functionality. Some race-cars, especially winning ones, are appreciated because they were machines that were 'the best' at a moment in time. No other car in the world was better. The parts that were broken or modified were a part of that car's story and adventure on the way to it being the best; they were designed, touched, and modified by the inspirational group of people whose achievement the car embodies. Other racecars are valued because they promise a unique driving experience. Being a racecar, they were a means to an end: winning for money, pride, prestige, or girls; so to the first owners, they were always worth less as a new car than used car. After the cars earned the money and girls, collector's had to choose from a bunch of cars that were used up or broken, so mileage was no longer a good heuristic for determining whether a car was healthy.