Well, there haven't been any official reports about the seeker. In various media one could read it is using r-77's seeker, that it is using some other russian seeker, that chinese worked with russians on developing its seeker and that chinese developed one on their own. No way to know which one of those is true. It seems logical and most likely motor is chinese.... as is the fuselage, which is slightly bigger than the one for r-77. All in all, i'd think its likely its performance is somewhere between performace of r-77 and late 90s amraam. But who knows. its all guesstimates.