I got gold on the first Indy race...I'm on the second race now...LAST PLACE...
I guess it's all luck...I changed the downforce to max on the indy track and it helped...I won by about 5 seconds...
As far as the other tracks, my lvl 20 b-spec driver sucks...and I can't even upgrade anything on my Nascar car...
Basically, as far as I can tell, 1 b-spec driver vs. a field of similar cars = loss...