Here is an easy way to gain 999xp in about 12-15 minutes. You can do it whenever you want and all by yourself!
- every fugitive in ai missions you kill, gets you 1 xp
- after a certain amount of kills you get 50 extra xp
- you can start a Rescue Easy mission all by yourself
- 999 xp is the max you can get per game unless you use a booster