A Car's Class is determined by the amount of Experience Points (XP) it has. Rookie Cars start with zero XP, and higher Factory Classes have more XP (see the table below). Cars gain additional XP from completing races, usually 0.05 XP per race. If a car does not finish a race (due to tire or engine problems, or crashing), it will not gain XP from that race. When a car is sold, XP and upgrades stay with the car.
Cars join races based on Car Class, which is determined by XP. Only certain classes of cars can race on certain Racetracks. Current Class = Car Class.
Car Class Level
XP Point Range
Factory Class & Current Class
The class in which a car begins is called the Factory Class, while the class it is currently in is called the Current Class. Factory Class is also abbreviated "FC".
Every car contains both of these fields, and when it is first minted the fields will be identical. As the car gains XP, it will move up in classes and that will be reflected by the Current Class. It is possible to race a FC Rookie Car all the way up to a Legendary Current Class by earning XP. For the average user who races regularly, this would take about a year to accomplish.
In order to protect the value of higher class cars (from lower class cars gaining XP too quickly), this distinction between FC and CC was made. While the Current Class determines which Racetracks the car can race on, the Factory Class is used for benefits and perks.
A car with a Factory Class of Rookie and a Current Class of Aero.
Can race on Ho-Pin Tung Circuit (Rank 3) and Petrov Raceway (Rank 4), based on Current Class (see Racetracks)
Can only claim Rookie perks (ex. cannot claim Loot Box drops for Factory Class Aero) based on its Factory Class
Even though a Factory Class Rookie can rise in classes by gaining XP, and one day become a Current Class Legendary, it will not inherit the benefits & perks of a Factory Class Legendary car.