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Modded Choppers

Default choppers, heavily modded with stronger guns, modified AI and most importantly, health. Copy to local to get the scripts and then copy paste the data/script folder contents to the game's data/script if you wish to use them in campaign, or enable the mod to use in other mods, and activate other functions held in the mod's main script.

The chopper AI when unaware generally stuck close to your general location, so I increased the range that they would search around the player to fly to when idle (besides buffing their guns).

Meanwhile the end chopper that chases you through Frustrum was more significantly revamped, now it no longer knows your location at all times, though it still sticks close to your general location to give the effect of it chasing you through the town.

UPDATE NOV 10, 2023: I did an even further update to the choppers, giving them health and more AI behaviours.
Using Dima's destructible bot framework, if you have any weapon that supports it or uses vanilla Shoot() or explosions, you can fight back against the chopper. Shooting it enough times will drive it off for a short period of time, giving you a breather. The modified Hunted choppers won't go down easy though, since they boast extremely high HP, and if you fail to drive them off before they open fire, you're almost as good as dead. Finally, you can get revenge on the chopper that chases you through Frustrum, if you hate it so much.

The main script activated by enabling the mod also contains other modifications for the base game's chopper levels and hunted modes: Rather than patrol around a randomized radius around you, they will instead fly to preset points on the map while searching (the patrol points are spawned in from an xml on init and the chopper immediately hooked onto them before they activated).
The important part is that this also controls the angle of their spotlights, to reduce instances of their spotlights pointing flat because you were on the same height as they were when they refreshed patrol targets.
The main script also contains the checks for hunted chopper status. If both choppers, as the usual Hunted mode structure is, get shot down, then the mode ends in a victory for you, although it doesn't save the score for your mode, so there is still reason to play the Hunted mode normally.