ORIGINAL: MAX NITRO
It will spin if you slow it down flaps down and up. It will duch roll on final if you go too slow. It snaps if you give enough elevator in turns.
Personal experience.
This is the Xtreme jets one.
Have you checked the incidence of the wings to confirm they are identical? Have you checked incidence of the wings to stab? Sounds like perhaps you may have a wing panel or stab out of incidence? Not uncommon with some low end Asian ARFS which could explain why some have had bad performance and others not....