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First, I want see if somebody made good simulations using A6 physics. If it is possible and somebody made a car which i want, then i can do research and will try to do it.


To my knowledge the Racer demo is the best car demo using A6's physics engine that's currently out there. There are ways to improve on it by tweaking the constants, models, and applying different acceleration/braking equations, adding hidden counterweights, etc.
But if you want a much more realistic or much more arcade-ish simulation then a general purpose physics engine will be only of limited use and you'll probably have to spend a lot of time recreating racing physics from scratch.