After hours of fidgeting with model compiling errors and textures, I have finished the L4D cars in multiple colors. Most of the time spent was making the models accept different skins. This was done to decrease filesize greatly and make switching colors as easy as possible.
Glass Models are also included which are just for pure convenience.
Models And Original Textures - Valve
Recoloring and Recompiling - UltaPonch
I would like to thank the people who assisted me in the progress thread:
In order to change the colors you will need to switch the model skins you will need to enter a console command or use a skin switcher tool such as this: