A few more interesting images.
From a promotion video:
A few more interesting images.
It is not as simple as sticking a new engine on a flanker. With the higher thrust, the entire plane must be re-designed to strengthen the body. It must go through extensive testing.
The question is, is this the best use of resources? I think it is better to just produce more J-20s with all this resource instead of upgrading a flanker with a new engine.