The Y-20 is quoted as a 200 ton class transport, MTOW 220 tons, payload 66 tons. Considering Il-76MD has a payload of 50 tons using the same four D-30KP2 as the current version of Y-20, the current version non-official quote of having 55 tons payload is quite believable, it's unlikely to go over 60 tons, but there’s no official clarification so it' just an educated guess. With increased thrust, Y-20B with WS20 should be the "completed" form that live up to the quoted 66 tons payload.

In the last Zhuhai, there’re model of elongated Y-20 and a civilian version Y-20 F100 that used four CJ-1000A. CJ-1000A for civilian use, has about 1 ton more thrust than D-30KP2, and certainly way more fuel efficient. WS20 has at least one more ton of thrust than CJ-1000A, possibly more.

Words are that the CFTE Il-76 are no longer testing WS20. Recent photos are the CJ-1000A.