1 - In event 3 add an action that sets the tyre marks opacity to car[Car].Speed/5.
This will stop the tire tracks becoming really dark when your car is driving slowly
2 - Add an event 'every 400 milliseconds' - 'set opacity of car_tyres to .opacity - 1
Add an event 'car_tyres opacity is equal to 0' - destroy car_tyres.
Ths will make the car tyres fade away slowly.
And yeah the headlights are awesome