I'm terrible at racing games, love them, but not very good at them, and I crash a lot and damage cars all the time in them.
If I pay 10 bucks for an IAP, I wouldn't like it when 20 game sessions down the road, I'm back at having to wait for a car to be delivered or a repairment to be done to my car.
And I'll bet that'll be the case, sooner or later, 'cause that's the way consumable IAP's works.
After a while, you'll have to cough up again, and that just sucks.
"To stop the flow of music would be like the stopping of time itself, incredible and inconceivable."