Frédéric
How does ride height and wing level effect the car/make a difference?
In general terms, the lower the ride height the less air that gets under the car so the better the car will grip through turns and the better the aero balance will be, but it may also bottom out under load at high speed or on bumpy tracks which can affect the aero balance of the car and also cause the car to scrape along the ground affecting top end speed on the straights and handling through the turns.
The wing level: the more wing angle you have the more aero drag your car will have so less top speed, but better grip through the mid to high speed turns. Low speed turns are mostly mechanical grip, suspension etc. Monaco for example you would run the car with more wing angle and Monza for example with less wing angle.