Ah yes I had that problem too. All white cars with weird circle tire textures. The way I fixed it was go into the CSM mod configurables tab and set 'texture resolution' to standard. Or FROM standard to high, what's important is that you select whichever one was not auto-selected. After making...
It was a long drawn out process for me too trying to get it to work. The steps i took were: 1. Download 3 files from here (http://www.gp4central.com/downloads/Grand%20Prix%204/) ((the .7z file that is 453mb is the same as the iso. the choice is yours but you dont need both)) 2. run the setup...