Question: How did Cain get the McClains from the other car to his. Did he change all the tires? Did he make the guy he robbed do it? Did they go to a shop?
Answer: He would have either made the other guy take his wheels off and put them in his "Cains" car to be changed later or he held the guy at gun point and made him change the wheels from his car to Cains and Cain left his wheels for his victim to use.
Answer: It's a Wonderful Life.