I'm trying to do essentially the same thing, I've got it working for about 1/2 my addon cars in a few dlc's but some of the cars are stubborn and I don't understand why. The model name and <gamename> strings are all under 10 characters. I've tried using plain text and I even figured out the correct hash#'s for everything but it still just won't work. I've even tried changing the global file in a few different places. Some dlc's have 1/2 the cars working and 1/2 won't, some dlc's just don't change the names at all. I'm completely at a loss for what to do.