Kurix, Thats a fun demo but you seem to be having the same realism issues that i get when running physics twice- i dont think you are, I'll imagine your engine itself is better. It certainly seems to be fast enough. I've just got mine to run fast by running two physics updates, the firt of which did a step size of 2X the second of which was a x1. this removed the rear wheel sliding that still occured. Pretty cool.