Rewards: 72 Gold, R$72,000
Location: SEASON 1
Unlocks from: Own Any Car in the Series
Maximum Required PR: 73.7
There are 51 events - 48 Trophy + 3 TT – with each car having a specific TT and 2-event showcase, and only the C8 Z06 will be able to be upgraded enough to open the last 3 cup races (PRs of 68.5 / 70.9 / 73.7).
Progress Rewards split:
25% - 9GC and R$9,000 [PR 49.5 using C8 Stingray, PR 52.5 otherwise]
50% - 14GC and R$14,000 [PR 54.7 using C8 Stingray or C7, PR 58.4 for C8 Z06]
75% - 19GC and R$19,000 [PR 61.0]
100% - 30GC and R$30,000
On its own a fully-upped Stingray can just scrape 76%, a fully-upped C7 82%, both together 88%.
As far as I know, upgrade costs for the C8 Z06 are not yet known...and of course it's not available for another month anyway (hackers excepted!)
#EDIT July 10# Again courtesy of Paulo on FB RR3 Trackside we now have the upgrade costs: