Well, i use the word "why" and a question mark. Not sure how that does not come across as a question, but that is my fault for not being clear enough.
But you answered it anyway, so thanks for that.
I tried with a 300+ car replacement pack. It worked fine, but the texture popins from the world ruined it, so i removed it. But i liked the idea. I suppose 300+ is just overkill.

I've noticed there's barely any carpacks around. Why isn't someone collecting the good once and making a pack, either for adding cars or replacing ingame once?
I have tried a carpack i found somewhere else, it was only replacing ingame cars, not adding. But i noticed that carpacks causes texturepopins, i'm not sure why as the amount of cars are the same, and the game isn't using all the vram.