If you can understand Russian, you would learn that PAK FA has exceeded its developers expectations in the fields of supermaneurability and supercruise speed.
Commenting journalist has stated that PAK FA is much lighter than F-22 and its maximal speed is 500 km/h greater than F-22.
It is unknown, what speed has he talked about, afterburned max or supercruise speed. It is possible that this is his own fake addition, but bearing in mind the official status of those video it is unlikely.
Data is short, almost none actually. However progrm-outside experts have calculated that if the PAK FA empty weight is 3 tons less than F-22, then T-50 can reach 2100 km/h supercruise speed using the current 117 engines. This is indirectly confirmed by Mikhail Pogosian. He has stated that Sukhoi company is completely satisfied with 117 engine performance and the engine completely complies all the 5-gen fighter engine requirements on thrust, specific thrust, resource and speed/altitude params.
Also guys from KNAAZ say that T-50-6 and T-50-7 prototypes are in the middle-construction phase now. T-50-7 will not be flyable.
Experts oppinions on T-50-7 purpose has separated to 2 points:
1 - T-50-7 is an RCS measurment and optimizations body.
2 - T-50-7 is another one prototype frame for resource testing while the previous prototype testing gave a lot of data to improve airframe strength and optimize weight. It is also rumored that CM part in the future prototypes and LRIP planes bodies will be significally increased, so they will be tested on T-50-7.
There are the other facts about static version:
1 - T-50-4 has enforcement plates on several parts and those plates must be removed and replaced by internal body strength improvements.
2 - As T-50 has exceeded initial speed parameters, then they must be utilized by more robust body allowing to withstand long 2650 km/h (2.35M) flights.
