Update PAK FA to FGFA level?
Why to?
Export weapons can be equal or inferior to Russian-internal usage ones
Why do you believe that FGFA will be superior to original PAK FA?
PMI prototypes are actually a PAK FA Stage-II prototypes, single seaters, with minor changes required by IAF for seamless usage and English localised software.
They are not FGFA prototypes but a planes for interim testing and evaluation by IAF to help them form up sane and substantial requirements for FGFA project based on T-50 platform.
FGFA will be generally a twin-seater PAK FA with Indian mission computers, partial Indian software and Indian weapons integrated. All of this with wide TOT and Make in India offsets.