I was considering doing a marathon run of this game and wasn’t entirely sure what would be defined as the end of the career. Would it be once you reach level 50, complete the final race (Sebring endurance), complete every race, win every race, or a kind of 100% where you win everything and unlock all the dealer bonuses?

Good question, I would be open to suggestions but for me it would probably be when you complete the Sebring Endurance event.

Any suggestions would be welcome though :)