And that's where the approach is wrong; quantity over quality. It's almost always the other way around. Do you remember the original "The Need for Speed" bac in 93' (I think)? That had only 7 or 8 cars, and each of them had accurate engine sounds.
I would any day, and I mean ANY day take a significantly lower car count, as long as ALL of them have been modeled accurately to real life specs - that includes, you guessed it, how they sound.
Its games like GT that set a bit of a bad example by giving gamers quantity over quality. T10 followed suit. Even in FM4, you have a handful of cars that do not sound right (though ironically they don't sound like weak home appliances).
This is exactly what happens when devs get caught in the car count wars. It's fine to have a generous amount of tracks, but I do not understand the need for having such a ridiculously high car count.
I say start slow, get all characteristics right. Then add more cars. That seems to be the most logical way of going about it.