Prestige Mode is available to players who have reached the final stage 24.
Prestige allows you to "restart" the game from the very beginning, keeping all the skills, gems, and catsomization costumes. Your car, all coins and spare parts will be reset. 
This action is irreversible.
When you enter Prestige, you gain a special icon with a number next to your nickname. The number indicates the Prestige Level.
Certain spare parts and skills can be unlocked only after reaching a certain Prestige Level.