My question is what is your reasoning to test fit the whole car kit? Usually test fit in our mind is test fit certain components, be it fuselage, wings of aircraft, body to chassis on auto kits, etc….

If it's the stance, you need to get 2 of the same kit. One would be your kit to work on stance. The second kit would be your kit to mirror the stance you were looking for. Does that make sense to you?