I use SparkIV when adding cars. It works fine. When I run into the cars that are police4 or policeb, it wont let me add. Only replace. How do I add car slots?

If you don't have EFLC, You cannot add any new models to the game. I am not really sure how this mod works, but I think it may help.

^^

Not true, you can use OpenIV to open the file and add the files police3 and police4. Sorry if I wasn't very detailed, I've never done it before. But I'm pretty sure that's how you do it.

If you don't have EFLC, You cannot add any new models to the game. I am not really sure how this mod works, but I think it may help.

While police3, 4, and b are the only ones that the game will recognize as additional police vehicles, I had no troubling adding a half dozen new car models to the game with only GTA4. The More Vehicles mod does just that, though it uses entirely new files instead of adding to the existing ones.

Sorry, I was misinformed.