The FP Piccolo requires a motor with a Kv of about 2500. There are two upgrade paths available: the Piccolo CP kit or the Piccolo Pro, which both require a motor with a Kv of about 3000.

The B20-31S and B20-18L have a Kv that's a little too high for an FP Piccolo so the flight time will be short, but they will be powerful later in a CP Piccolo.