If that were true, then every pro driver would run the exact same setup as each other, at every track. While it is true that a good driver can go pretty fast with a well set up car, let them make some adjustments and watch their lap times drop. Pro drivers are good at driving, but also really good at knowing what adjustments to make to make the car handle exactly the way they want. When a pro is fighting their car, their lap times will still be fast, just inconsistent.

Cherry, have you ever travelled to a big race outside the PNW/West coast?

To the guy that found 2 seconds after a bunch of track time, unless your car had a bunch of things fundamentally wrong with it, I seriously doubt very much of that two seconds was as a result of setup changes. You are going faster because of practice. If all of your lap times are within .5 seconds of one another, then setup changes will catch a tenth here, and a tenth there. Big gains in time are from you driving better. Some of your setup changes probably helped to make the car easier to drive. You can see how right I am if you undo all the setup changes you made, and your lap times don't change much.