I am not sure I understand this.  German cars already cost more, there is likely a reason people want to pay more.  Lets say that American made cars are inferior - increasing tariffs will ensure Americans will buy more inferior cars.  This ultimately should cross over into all goods.  Ultimately Americans will have to buy inferior over quality - does this not diminish the American standard of living and burnish what it is to be American.  Rich people will continue to buy quality, the working class will need to find satisfaction a little deeper in the abyss.