1-quoting from the basic concept page:
Performance Index (PI)
The Performance Index, or PI, of a car is the sum of all the attributes of that car. You can increase your PI by buying new items: each item unlocks performance points that can be used to improvev your car attributes.
This mean that for example buying mud guards will get me more PP or increase my cars Pi somehow or is talking about the the widget system that apears before every race where i can buy 1 race items?
and now quoting from the same page but the R&D screen section
Each of your cars will unlock 3 PPs each time your driver levels up.
it means that i can assign my current points in my ugly looking rookie car and when i get a better looking new one it will have PP ready to assign? i just dont want to waste points in an ugly car.