J20 jets have been equiped with new engines - WS10B or WS15 that allow the jets to reach a state of supersound cruise at 1.5 Mache without further accelation. This jet is able to have over 2000 km fighting radius - i.e. it has over 6000 km range of flight without refueling. Also, its stealth ablity is super - about 0.01 m2 from the front, comparable to J22 jets. More deadly is that J20 can carry 6 long range anti-air missiles that can reach over 200 km targets. J20's radar can detect stealth objects including F22 from 300 km away.
There is no doubt that J20 jets will change the war style of future, or there shall be not new war in the areas surrounding China because of the J20 joining the PLA Air Force. Think about it, folks!