Kevin
Reducing driver weight has a negligible impact on Star Rating. It's been a while since I last payed close attention to level during training but IIRC it is only the increase in Stamina that increases the Level/Star rating.
This is why the optimum training strategy is to fully train Physical before the other areas because this allows driver weight to be reduced very quickly.
Training Driving Ability and Mental first increases the Level / Star rating which then makes it much more difficult and time consuming to reduce weight.
That is awesome information, thank you for your response and time.