I'm afraid these are very industry specific terms ("Quarter Model", "Full Model") that I don't have experience with.
Please check out the automotive example page. It has a fair number of examples of models of different car systems. SystemModeler uses the Modelica language, which is widely used in industry. If you search online for "Modelica Full Car Model", you will find many resources. I am afraid I'm not familiar enough with this subject to help you search through them. I would recommend contacting Wolfram Technical Support by email (support@wolfram.com). Let them know you are interested in Wolfram SystemModeler for this kind of model. They will be able to find someone more familiar with this subject who will be better able to answer your questions.
Here is a video about how Wolfram SystemModeler and Mathematica are integrated:
http://www.wolfram.com/broadcast/video.php?c=246&v=1155
There is additional information available as documentation.