Here's a point-by-point comparison of frontal RCS for J-31 vs. F-22
Transparent RAM-coated cockpit canopy: J-31 and F-22. Tie.
Continuous curvature upper radome. J-31 and F-22. Tie.
Faceted lower radome. J-31 and F-22. Tie.
DSI (diverterless supersonic inlet). J-31 only. This means J-31 is...