[JoeT]

To add new cars all you have to do is look online at the specs of a car you wish to add. Once you have the vehicles specs like weight, wheelbase, hp, tq figures, gear ratios, coefficient of drag(.32 is pretty average if you cant find the actual wind resistance figure) and quite a few other specifications. Go to the "Add car" option and just type in all the specs you have. After you have added all the specs, press the F1 key to save then the F3 key to test. Press the F3 key and click down a few to "optimize launch rpm" let the computer figure the best starting rpm, once that finishes(8 sec or so) then press "esc" back out to where you can alter the specs and you'll notice that the launch rpm has changed to optimize the best acceleration time. You then press F3 again and run the acceleration test or track test or any other test you want.