Microsoft Japan released today the PC DEMO version of the Forza Horizon 3 what you can download from the Windows Store for free. The demo available with English voice and with Japanese subtitle and you can play online with it.
The online mode support the team play with up to 12 players. Microsoft Japan on the official blog page also published the minimum and the recommended system requirement for the DEMO which is nearly the same as for the full version of the game.
If you still think about the buy the game, download the DEMO and try it for free.
Microsoft Japan Blog: https://blogs.technet.microsoft.com/xboxjapanblog/2016/11/04/forza-horizon-3-windows-demo/