I did them all at the beginning. Delivering the tank to the port, so i can get 100% completion.
Btw i have classic lighting on - it's just the new update, that made everything look hella bright and broke all mods >_<

I would recommend the "Classic Lighting" Option in the game to get back the old-school feeling if you like of course :)
The biggest problem are the missing packages and side missions like Firetruck or ambulance. You can't do them with all the gangs one-shotting your vehicle so I had to install a mod sadly. If you do them early on without any of the gang war stuff, you're good to go, but yeah... Doing them late in the game is a automatic RIP.