I personally roll my own because the inputs are in the same form and units and tables as the extensive K&C and Tire databases that are maintained of thousands of production, experimental and competitive vehicles that have been measured over the years, Plus, if you are gonna run a nonlinear simulation to geth the steady state and transient results in Step, Bode, Constant speed and constant radius tests, you can do it easily all in one blast.
Besides, we use synthesis softeware mostly, (put in the answers, get out the questions). That means what tires, steering and suspension parameters does it take to produce BMW like handing in an Oscar Meyer Wienermobile Styling Studio proposal. Hey they're just appliances...
