For both of them, the assets in Blender have to be 100 times the actual size to begin with. You can control the scale of your object to sync with unity in blender by going to Scene -> Units and making sure the Unit system dropdown is set to Metric.Blender to unity scale as you can see in unity wheel collider is scaling too large depending on car scale plus rotation of car is not correct because as i noted in image the small circle on wheel collider must be at bottom side.
