the challenge is to survive the highest amount of time on 6 stars, you cannot attain the stars by going into a restricted zone (area 69,easter basin) you must attain them by committing crimes.

you can't use the rhino, hunter and hydra as vehicles.

you can't use any cheats, but you can load a 100% save with your choice of weapons, stats and armor

it would be a fun idea to try such a challenge, maybe even track the kills.