Assetto Corsa does not have native HTC Vive/SteamVR support yet, but ReVive is the next best thing - and it works!
Follow these steps to enable your HTC Vive in Assetto Corsa:
When compared directly to Project CARS, Assetto Corsa is my personal choice. I prefer the handling in Assetto Corsa as well as how it feels when the weight of the car shifts under cornering, when the back end loses grip and when the car starts to understee