Is there a website with accurate data for the physics? I can only find the general specs for the cars, and that's it pretty much. How do you usually do it?
Forums, Patent documents, Books, Scholarly papers, Workshop manuals. Find someone that owns and is passionate about the vehicle. Ask questions. It is a full on research project, but at some point you will need to make a few educated guesses if you don't have all of the necessary data.