FPV RC Car Gimbals are hard, but I believe this one will be the best ever. It's great for an FPV drone right out of the box, but the vibrations from a car are a lot more. Here is HEQs contact, if you'd like to encourage them to work on the yaw twitching issue when used with FPV RC cars / Rovers - https://store.hequavtech.com/pages/contact
This gimbal has been awesome to play with. On very slow vehicles, it works fine and there are no shakes. Once you pick up enough speed, the yaw goes crazy. I'm sure they can fix this issue and I will update as soon as they do!