I found some in x64e but after replacing them with another model the car in-game isn't changed.
Also is there a thread telling us where certain files are located? Because I looked through the forums and couldn't find any.

Thanks.

So I got my game updated, I got a trainer, yet whenever I choose a DLC car for online it stays for a few seconds and then disappears, nothing else, it just, disappears. Sometimes it's instantly, sometimes up to 10 seconds. I really don't understand why. Only about 2 lowriders seem to work properly.
Any fix?