What's done: 1. Completed the storyline. 2. Completed all side quests / missions. 3. Found 100 hidden packages. 4. All unique jumps are done. 5. All cars for Love Media have been taken away. 6. Completed all the riots.
There are also very unique cars hidden in the garages. In the garage of Shoreside Vale sits the indestructible Hunter helicopter. And you can find the rest of the vehicles yourself. P