Gran Turismo 5 is the first game in series to include both mechanical and external damage modeling, including a real-time deformation engine that will process model deformation according to the speed and angle of impact. Gran Turismo 5 features 1031 cars in total divided into two categories based on the damage model.
Standard cars will feature a basic damage model with dirt, scratches and dents appearing on the car in the event of an accident as well as internal, mechanical damage.
The “Premium” cars will feature the full damage model with more accurate damage such as panels capable of being ripped off.
You can check the full list of cars under each manufacturer here.