Air cart is a great experience, one of the best really. I use to be prone to VR sickness. It has pretty much went away now after all the time I spend in VR.
Smooth turning actually works for me if I'm in a cockpit. No problem for the brain to turn in a plane or ship. If i try it in an FPS while sitting or standing though, its instant cold sweating. The wonders of the human brain. BTW, air car was a delight and i was very surprised by its quality. My only wish is that i could actually hold that steering stick with my touch controls and use it to control the vehicle instead of the thumbsticks.