@Pavelninyerola You can use this mod:
https://www.gta5-mods.com/scripts/the-character-vehicle-mod-net
It works with any replace or add-on cars.

So I like downloading add-on cars, but I'd also like to see them spawn naturally in traffic without my game crashing. I can get them to spawn naturally in traffic by adding them to popgroups.ymt, but I've been reading about how a lot of car mods don't have proper LODs so they'll be rendered in full detail regardless of distance. And the more cars that do that, the more strain on the game and/or PC, meaning more crashes.
But what I haven't been able to find is if there's any way to tell if a car mod has LODs. I'm assuming if I could figure this out and only add cars with LODs to my popgroups.ymt then my game would be a lot more stable.

Follow-up question: In the "lodDistances" section of vehicles.meta files, there are 6 values, but I don't know what they mean. Can someone explain that? And if a car doesn't have LODs, would modifying these values do anything to improve stability if it's spawning naturally in traffic?

One more question: There wouldn't happen to be a relatively easy way to modify car models to add LODs would there? I'm assuming the answer is "no" since a lot of modders don't include LODs in their add-ons.

Last question (seriously): Does increasing the number of vanilla cars in popgroups.ymt sections decrease stability? For example, I like to see rare cars in traffic and just more general variety, so my modified VEH_FREEWAY section has 162 vanilla cars. That's not increasing the number of cars that spawn, just the variety of cars that can spawn, so I don't see why it would make the game less stable, but I also wouldn't be surprised if it did.