[Primorsky]

>We are 50 years ahead of the Russians when it comes to stealth technology.

Sounds like BS.
Soviet Union and Russia never stopped development of radar absorbent / composite materials.
Soviet physicist named Pyotr Ufimtsev made important calculating turned out to be possible in making aircraft with stealth technology.
Stealth technology is not new discovery for Russians.

[ErnstStavroBlofeld]

The Germans in WW II developed stealth technology by the Horton Brothers. The developed the HO-229 in 1944:

Here is the Stealth Bomber and the Ho229 compared together. It is all right to admit that you are wrong.

[MediaMole]

Yes, the theory behind stealth was a Russian discovery, but the aircraft designers never put it into practice. They have had great designers and mathematicians, but the political structure didn’t reward risk takers.

At this point, the new fighter is more like an F-18E, with reduced radar cross section, rather than true stealth.