It looks like generally DR correlates very well to finishing position, although there are obviously outliers (the best time trial player has never done a daily race, at least not on that account).
If you're golding these on the regular you have the pace to be A rated basically.
Some numbers for those interested:
DR | Number of unique PSNs | Average position | Percentage with at least one gold |
S | 39 | 1411 | 100 |
A+ | 5486 | 7150 | 90.2 |
A | 16346 | 17692 | 71.5 |
B | 66306 | 34761 | 39.9 |
C | 67609 | 50310 | 17.7 |
D | 124840 | 67814 | 6.0 |
E | 186123 | 72662 | 4.6 |
The percentage of players with at least one gold might change a lot if you take away the easy Sardegna one. There might also be an effect from second accounts but don't have a way of knowing which ones are second accounts and not a unique person.