Now that my rerun technique has been honed, I wanted to share my thoughts on farming for cash. It's now harder to come by and gets flushed away faster than GC. Late in the game the GC upgrades are rough, but so are the cash upgrades.

Based on the $R per minute of these two races, the shorter one will always be the better choice:

Campionato Scuderia Ferrari: Flag Racing Euro Race Day: Head to Head.

$R 112,950 + 7050 clean racing bonus. This assumes 100% daily race bonus and Manager. That works out to $120,000 per 3 minutes, or $R 40,000 per minute. 

Endurance Kings: Mastare Prototype Championship: LeMans (10 lapper).

$R 623,000 + 30,000ish per 28.5 minutes, or approx $23,000 per minute.

My device takes about one minute to force close and restart a new race, which brings it down to $R 30,000 per minute. Between the higher rate of return and the fact that you can actually put down the device every three minutes if you want (the 10-lapper is great sometimes, and other times it feels like a chore), the F14T race works best for me when farming $R.

Again, this only applies if you are flush with GC (edit: and if you have access to Campionato Scuderia Ferrari).