There are a variety of ways to increase your equipped Driver and/or Component stats in game:

Boosts - Boosts add a set amount of stat to a specified stat. For example, if a Boost includes +10 Overtaking, the equipped Driver will gain 10 additional Overtaking stat.

Featured Assets - During a Grand Prix Event, there will be assets that are featured. Featured assets gain a set percentage increase calculated from the base stats of that asset. For example, if a featured asset has 10% stat increase, you will see their usual stats increase by 10%.

Sponsor Tasks - If there is a Sponsor Task with a boost to a particular stat as a reward, this will provide a set percentage increase calculated from the base stats of the relevant assets. For example, if the Sponsor Task reward provides a 10% increase to Tyre Management, you will see your equipped Driver's usual Tyre Managment stat increase by 10%.

Race Start - The increase in performance gained during the first lap of a race is also calcuate from the base stats of your equipped loadout.

Track Stats - Tailoring your loadout towards a Series and Track's Track stats will provide you with enhanced performance during the race. This performance boost is calculated based on your equipped loadout's base stats plus any other applied stat boost, such as the above.