@ReNNie Agreed, but it does run with higher polygon models and he says real life cars, not all of which are like that reventon.
I'm simply surmising that if the car runs without the script, then we can definitely point to the script as being the source of the issues, for those particular car models.
If he is running multiple instances as you said, then definitely that will worsen the problem as will poor system specs and the wrong config.
So Op can stop using mod, stop using mod with this vehicle(s), tweak his config, or buy a threadripper with 2 3090s.