The 9920 is slightly upgraded. It has dual wires everywhere, the throttle curve was adjusted, and it has been more optimized for lower cell counts. It still has the same BEC chip as the 9920, though.
SH Z-Car, Custom Crawler, 8s Savage, 12s XTM XLB 1/7 buggy, 4wd 4-link rear/IFS Pro4 truck, Custom Hyper 10 Short Course, Belt-Drive Mammoth ST 1/8 truggy, 4s 17.5 MM Pro HPI Blitz