Leveling up cars currently gives the player no reward other than a 5% discount for cars of that manufacturer per Lvl50 car, with the limit being 25% so 5 cars. Since Update 6 is finally getting rid of those pointless Level Locks for Upgrades, it’s about time to give players an incentive to drive their cars, or whatever.
Car Points from all cars of a manufacturer should be a shared pool, at least after getting 5 cars of that manufacturer to Level 50. This way, after having Max Leveled 5 Mazdas I will be able to immediately get to work on my next Mazdas with the surplus Points from other Mazdas.
One issue I see with this though is that there are some manufacturers that have less than 5 cars, so without multiple duplicates neither the discount nor this proposed shared Car Point pool will be unlockable. In this case, simply reduce the number of cars needed for the discount and shared Point pool to the amount of cars of that manufacturer +1.