Word of warning. If your driver's level 0-15ish, he'll be quite rubbish even if your car has more horsepower and is lighter than the rest of the field. This is especially nightmarish if all your cars have to be the same, such as the Lambo Gallardo cup. Once he gets to about level 20 he'll be much more confident with his overtaking and actually go for gaps instead of just lagging onto the exhausts of the car in front while the three behind slip by easily. Hopefully by then you'll have a good roster of cars, coupled with the better driving skills of your Bob you should be able to win most races easier. I'm on level 30 b-spec and I've basically just handed down my FGT from my A-spec to my driver who owns everyone.
Basically, don't just quit if you're losing because it's all about the XP.