today launched a new version of X Motor Racing
along with a demo that gives you the chance to try out this indie racing simulator that features high precision physics simulation, fully customizable physics model, different tire models, telemetry system, SDK for the external control and getting in-game physics data etc. XMR contains VehiclePhysics tool to tweak physics of the cars. It includes an editor to add new cars and tracks to the game.
X Motor Racing can be purchased by visiting this page