wwddww34, the D3.5 21.5 (TEP 1083) is still on the
ROAR approved list. 17.5 and 13.5 are no longer allowed, but the 21.5 and mod turns are still on the list.
D4, R1, ORCA TX, D3.5, Team Scream, Actinium...any of those would be a good choice for a ROAR legal 21.5 motor.