User blog comment:Visually/Don't do "Summer's Over Update" before claim your mastery rewards./@comment-109.80.17.101-20151014125318/@comment-26536836-20151017143618

Yes, that's so true.

If you want to get some rewards from TLE(Time-limited event), you must have fully pro-ish car.

But one thing you have to think about is he or she was still on season 7. I don't think there has good farming spot except season 9 because almost all the race required 2 laps. Of course, if you can pro it to do the mastery challenge is good idea but I don't think it is possible to get the all the necessary cards only from the daily boxes. So season 9 is best choice before have good fully pro farming car.