Just some extra information about this series, over and above the release notes details...
There are 57 events (54 trophy + 3 TT) with each of the three cars having a Showcase and TT, and the Gold progress rewards split out for 25-50-75-100% at 9-15-20-32GC.
Provided you have all three cars then 75% can be reached with one at roughly PR79:

This is courtesy of there being several tiers opened up ahead with of course a couple on non-cup/non-PR events which can be done on each