F-22 - Nozzels do not protrude, they are highly angled on the ends and protected from IR signature, also made of very advanced material to further reduce IR signature:
T-50 Nozzles protrude far back where their IR signature is not hidden or protected. Ends not angled, round all around. IR Missle magnets.
I have no doubts that the T-50 has good radar stealth...I do not think it will be as good as the F-22 in that regard...and from what I see with my own eyes, it will be far less stealthy from the rear in IR.