Board Thread:Game Discussion/@comment-94.228.80.91-20180423160213/@comment-2605:A000:132E:8291:BCD8:300D:61E6:F8F2-20180423213547

That's a tricky question. I don't think there's a real honest answer. I've had cars way under FU, then Fully upgraded them and gained nothing. Then other times, it made a huge difference. It depends more on the players skills, and somewhat on each car. But I don't think there is any standard you can depend on.

One thing you could do, upgrade the car, make a few runs and see what happens. If it doesn't help, restore. You will lose your time, but if you're consistent, you can regain your position fairly easily.