Hi! I've worked with unity's wheel collider in the past, so I've learned a few things:
- Set the car's physics material to zero or very low friction. (make sure the friction combine is multiply and not minimum, because that doesn't work for some reason.)
- increase the side to side grip a little bit. The front tires are slipping when trying to turn at speed.
- reduce the turn strength when at high speeds. it's possible to manually accomplish on a controller, but not easily on a keyboard. turning the full amount at speed makes the tires slip and lose traction.