Once again I'll say - That is not the way it works. The 2 km does not apply to an aircraft determined to be a threat. In the case stated above the alarm and display would go off at x secs regardless of the distance. I am not sure what the number of seconds is but it is based on a safe reaction time. The warning would be limited by the reception range of the FLARM set up and any limitations the pilot has set in $PFLAU portion of the configuration file. This would be true stealth or not. The specifics of how the threat is painted and the audio warning is left to manufacturer of the display device.

Proximate aircraft which are not a threat are only displayed if they are within 2 km and +/- 300 m, etc.

XC