Unresolved

Driver SA and driver age

Hey guys, can some1 please explain the difference between drivers Special ability?
I mean is it huge difference between common racecraft and rare racecraft abilities?
For example is it better to rake 8 talent driver with rare racecraft SA or is it better to take talent 11 driver with common racecraft SA? 
And how does driver age impacts training? Will 18 19yrs old driver train up much faster then 24 25yrs drivers?

Age does not have any impact on training. What matters is difference between your player level (8) and how low the driver's level is.
The higher the level difference, the higher the improvement after each training. If your doctor is 5 stars, your drivers will lose less energy after each training session.

I don't think nobody can answer about the difference in rarity for each ability but legendary is the best by far.
You have to buy the highest talented driver and then you have to pay 200 tokens to add legendary racecraft special ability. There is nothing more to say. Racecraft is by far the best special ability.