Asphalt Legends Unite

Once you unlock a car, you can then collect a set amount of blueprints of that car to star it up, which unlocks more stage upgrades, allowing you to upgrade that car to a higher rank. Every car can be starred up at least twice, but some 3, 4, or even 5 times. The description here is a little misleading - you only need to star up cars in general 30 times; it doesn't need to be 30 different cars. So starring up a car twice counts as two towards this achievement.

The strategy for getting car blueprints to star up cars is the same as unlocking the cars in the first place. Refer to the "Owned!" achievement solution below for the best places to find car blueprints to unlock cars and then to star them up too.