As a beamng player i really think that with scratches on paint of cars after an impact would really suit into beamng realism. Now with the dirt physics i think when a car goes through rough terrain such asirt, gravel, wet mud etc. the cars get dirty. To suit this i would reccomend adding a car wash which could be added to gas stations in maps such as eastcoast and the city usa map. These carwashes clean the car ,Also adding car water physics such as after a car goes through the car wash it has water drops that blow away after driving off from the carwash. I think these ideas i listed will go well with other beamng players who play the game for the realism.