Androids.
Imo, they were already around the level of Goku/Trunks(Mecha Freeza arc) at baseline... And all it would take for them to skyrocket beyond that is either grabbing one of the Saiyans directly, OR absorbing their ki blasts(an ability that the Saiyans would be completely unaware of, so it's likely to work initially.)
Aside from that, #19(and presumably #20) was durable enough to soak a beating from SS1 Vegeta for a while -- and Vegeta was considerably more powerful than either of the Saiyans here.