Just remember, these are based on budget. If you don't have much budget, and you try to hire experienced drivers and team members, you won't have enough money for your car, and your ratings will suffer.

I've made a few more adjustments so the budget can be a little less than the previous optimal to see the beneficial effects of having experienced team members.

So if I understand correctly: With "car development", it means the car within the racing team.

I thought car development boosted research rate, and racing boosts marketing overall?

Car Development will increase your team's XP points and increases your RnD research skills (used to unlock new designs, and little bonuses to designing stuff).

If you move the slider to Winning, you will lose team XP, but it increases the chance you'll do better in the races.