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Players earn XP that progresses them from one level to the next by completing races in the available racing game modes (Custom Games, Time Trials, and Quickplay) and earn rewards as you level up.
XP points are earned through completing races and time trials and allow you to level up in the game. As you level up, you can earn different items in-game.
Power Cells are an in-game currency that is earned when you complete races in Custom Games, Time Trials and Quickplay. These can be used to purchase loot capsules from the in-game store.
This is the primary way of getting loot capsules. The other is through community participation.