1. As a gamer I want to have a simple track builder, so I can race on any road in-game I want.
A good easy track builder. Create your own tracks using Google maps for example.
Height differences and track length+width for example can be reasonably accurate then.
You can edit parts you want, add trees whatever. And suddenly the road in front of your home is a track or practice location
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2. As a gamer I want to buy every car and engine type in a game. So I can drive exactly my own car in a game. I want to be able to upgrade it accordingly
If you add a car to a game, add all the types as a developer. I mean in engine choice, luxury trim etc.
If you're poor in-game or want to tune you may buy the base version of a car. If you want a fast car immediately you buy the better car.
So for example, add a Ford Focus.
Base model is an 1.0 ecoboost, but you can also buy a diesel, an ST, RS whatever. You could even completely rebuild your own car...
I mean, you can always drive the fastest type in a game. But why not a base model?