I also noticed that when it rains, I can't even reach 300 km/h in certain sections, even though it should be possible. Were the tracks set up so that you can only reach a certain speed when it rains? With the grip I modded, I should have easily been able to reach 330 to 340. I drove with 0 wing and Overtake to test this. I also noticed that the standard setups work best and my own setups are placebo. They have programmed the game completely to the standard setups and think that's enough for us. Who needs their own setups? Then I noticed that in the rain, ERS assistance should be turned on because it is better dosed and you have ERS for longer. So the ERS is always turned on and off in places. Anyone who drives with manual ERS in the rain is at a big disadvantage. Try it out for yourself.
To make us players believe that every change to the car has an effect that doesn't actually exist is, to put it mildly, pretty cheeky.