I run the Hobbywing SCT Pro in mine, with a 1950 Tekin T8i, geared 19/43.
1900-2100 will be what you need. Darren runs an RX8 with 2050 Tekin T8. Hunter Kinsey runs the RX8 with the same 1950 T8i but geared 20/43.
I'm not sure what Darren's car is geared at, pinion wise.