I've played Horizon 3 for a very long amount of time, and as I gained the experience I needed to succeed in that game, I feel I have become well versed enough in effectively upgrading and tuning a car to be competitive. However, I have recently purchased Horizon 2, and from what I understand, the PI system, and therefore what makes a car competitive, is quite different from that of its successor.
As such, what's different from Horizon 2's PI system compared to Horizon 3? What would I want to focus on in competitive upgrades that I wouldn't usually do in 3, and in what order? How does the class balance differ from 3, and in what way?
Many thanks in advance for any answers I may get on this subject.