Oh well, old habits die hard...

51 Events - 48 Cup and 3 TT, in which each car has its own 2-event showcase +TT
GOLD REWARDS
25% :  10GC
50% :  15GC      ...requires PR 87 to reach
75% :  21GC      ...can just be reached with fully-upgraded RS alone (PR 90.9) 
100% : 33GC     ...requires PR 92.6 and can only be reached with the 935 (at a cost!)

(I believe the 935 needs 1125GC upgrades for this)