The usual extra info on this series for the Porsche 911 RSR...

There are 42 events (36 Trophy + 6 TT) and the rewards 25-50-75-100% are split 9-15-20-31GC.   The Race Day-winning PR88.9 gets you past 75%...

No surprise that to complete the series needs upgrade pattern 5353433 which costs a further 400GC.