Use parts to level up your cars.
◎ Part selection
Select parts to level up your car. The star level of the part and the number of parts you use will determine how much your car will increase in level.
Tuning your car costs coins, as well as parts. The cost is determined by your car's current level and the quality of part(s) you'd like to install.
◎ Using Unique parts will give 2 times the XP compared to normal parts.