How about the simple things in real life racing i.e.

1. Off line rubber build up
2. Dirt,Oil,Water on the track
3. Car dirt build up on screen and body
4. Oil flag, black and orange flags etc
5. Safty cars
6. Rain,spray etc
7. Buzzing the engine

I'm sure the older version of LFS let you over rev and damage an engine..or did I dream that

All of these have already been suggested. Please read the stickied threads before you start making new threads.