The goals and PR requirements. (Coding error in S4G2 sets PR req lower than S4G1. Cannot be reached anyway without clearing S4G1.)
Also note most events finish when goal is achieved, so are very short and award very little DriverXP.
Will update post with my strategy which may help others later. My strategy usually focuses on low M$ cost (tuning) and to up driver as much as possible by farming (that we have to do anyway) during event to open invitational as soon as possible.