Agree, either hobbywing platinum 120 V4
or tribunus 120.
My 516 has the xnova 4020-1350 paired with HW 120 V4.
Servos are mks 9767 and futaba bls276sv.
Consider fitting the optional carbon fibre boom as well, it helps with getting good centre of gravity while no problems getting canopy on over the battery. Lipos around 4200-5000mah work fine, i haven't tried anything smaller.
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