It's okay, it's not about life :-) I figured out the track restart thing later and as you say, that basically solves the problem. So thanks for your mods and see you later.

I don't know the cause of this issue. It doesn't happen to us.
(If it runs fine after the restart, then it's probably not a problem.)
If you are concerned about it, you should ask about it in the general forum.

One more thing. What I wrote always happens on the first pass of the track, if I restart, on the second or next pass everything is fine and the car behaves correctly. Which is very strange and I don't understand it very well :-)

I was able to verify this.
The speed is too high and there is not enough grip.
If you change the tires to slick tires B, the car will not slide.

Since we are modifying a car that has been perfectly tuned by the developer, the CONFIG MOD car will inevitably be unbalanced.
If I find any other strange parts, I will try to improve it as much as possible.

I agree with everything yoI agree with everything you wrote. However, that is not the case here. The car (your mod) was completely stock, tuned, no modifications and I tried it on a speed test track. That is, driving it straight through with no cornering. What happens is that at about 220km/h the car suddenly swerves spontaneously, mostly to the right. For completeness, I should add that I also have the original version of this car, as it was in the game, with the tuned I4 DOHC 4x4 engine, which reaches 330km/h and this instability problem is not there.

Thanks, lada.k
My CONFIG is tuned with parameters that allow it to complete the race track in less than 2 minutes (except for drag racing cars, etc.). The adjustments are made without tuning, so if you increase the power output by engine tuning, etc., it is easy to lose control.
Some cars are extremely vulnerable to cornering and bumps, so avoid going off course, and also careful acceleration and deceleration may be required. Also, if the RPMs are too high while the car is not moving fast enough, the gears will spin out of control.
Countermeasures include changing tires to race or slicks, refraining from excessive acceleration to avoid spinning the gears, and using back gears to slow down when cornering.

Hi, as with all your mods, perfect job this time. I have one problem, though. This is (so far) the first car from your collection that I have driven, and unfortunately at speeds above 200km/h it starts to "float" and becomes unsteerable. Do you know where the problem could be?