Not the KAI T-50 Golden Eagle. Sukhoi's PAK FA project T-50 prototype.
And yes, the T-50 could very easily be the "Raptor Killer."
It's more like if the U.S. has something the Russians don't, then they have to have it, or the Russians have something the U.S. doesn't then they have to have it.
There's still a minor arms race going on, it's just that rapid aeronautical advances are not happening like they where in the 50's and 60's.
Example, if the U.S had a rail gun that was small enough to fit on a tank, it could be a game changer and the Russians would have to have it themselves to stay technologically equal.