5th generation fighters like j 20 & 31 are really very costly to build and much more costly to maintain.....
They require up to 30 hours of maintenance for an average 1 hour flight...
Even a single scratch can demolish stealth feature of the jet.....
Any minor change in the outline could be prove fetal ...
So PLAAF should concentrate more on 4.5th generation boys which are extremely capable , easy and cheap to maintain and very affective on the dogfights and ground targets...
Further they should concentrate more on their projects for 6th generation fighters so that they can develop before US lokheed martin and northrop and Russia's sukhoi....
This will be marvelous...